JPS6347585Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a suspension system for a tilt cab in a cab-over type vehicle.

[Conventional technology]

In vehicles where the cab is supported to the vehicle frame via a suspension spring and a shock absorber, when the cab is tilted forward for engine maintenance, etc., the suspension spring's spring constant is small and the cab tilts from side to side. There is a problem that the tilt is unstable.

In order to prevent such wobbling of the cab, for example, as shown in Japanese Patent Application Laid-Open No. 57-155169, when the cab is tilted, the link lever that supports the cab with respect to the vehicle frame hits one end of the cab mounting bracket. Although a structure in which the link lever is prevented from swinging has been proposed, such a structure may not be adopted depending on the suspension method of the cab.

[Problem that the invention attempts to solve]

SUMMARY OF THE INVENTION An object of the present invention is to provide a highly versatile tilt cab suspension system that eliminates sideways vibration of the cab when the cab is tilted by locking the suspension function of a typical cab suspension mechanism.

[Means for solving problems]

In order to achieve the above object, the structure of the present invention is such that the shock absorber connected between the vehicle frame and the cab is provided with a clamp that prevents the shock absorber from expanding or contracting.

[Effect]

When the clamp 42 is tightened by a hydraulic actuator or the like, the operation of the shock absorber 4 that supports the cab 3 on the vehicle frame 1 is locked. Thereby, when the cab 3 is tilted about the tilt axis 15, horizontal shaking of the cab 3 is suppressed.

[Example of idea]

The present invention will be explained based on examples. As shown in FIG. 1, in a cab 3 equipped with a suspension, an intermediate portion of a link arm 5 is supported by a bracket 16 fixed to the front end of the vehicle frame 1 via a tilt shaft 15, and this rear end supports a pin 21. It is connected to a bracket 23 fixed to the side frame 2 of the cab 3, and a suspension spring 6 is interposed between the link arm 5 and the bracket 23.

Further, a shock absorber 4 is connected with pins 14 and 13 between the front end of the link arm 5 and a bracket 12 fixed to the cab 3. Such suspension mechanisms are disposed at two locations on the left and right sides of the front end of the cab 3. Although the rear end of the cab 3 is not shown, it is supported by the vehicle frame 1 with springs at two locations on the left and right.

In order to suppress excessive imbalance between the left and right suspension mechanisms, a stabilizer 7 consisting of a torsion rod is supported by a pair of left and right brackets 16 with bearings 18, and both ends of the stabilizer 7 are bent rearward and attached to the pin 1.
9 to one end of the link 20. The other end of this link 20 is connected to the link arm 5 with a pin 22.

In order to tilt the cab 3, a tilt lever 8 is supported on the vehicle frame 1 with a support shaft 17, the rear end of which has a pin 24 at one end of a link 25, and the other end of this link 25 has a pin 26. and are respectively connected to links 27, which in turn are connected to a bracket 29 fixed to the side frame 2 with pins 28.

The rod of the actuator 9 is connected to the middle part of the tilt lever 8 with a pin 33, while the cylinder is connected to the bracket 3 of the vehicle frame 1 with a support shaft 31.
Supported by 2.

In the present invention, a clamp 42 is provided between the shock absorber 4 and an outer cylinder 45 surrounding the upper half of the shock absorber 4 in order to prevent the shock absorber 4 from expanding and contracting when the cab 3 is tilted. As shown in FIG. 2, this clamp 42 has a bracket 44 fixed to the lower end of an outer cylinder 45, and supports one end of a pair of clamps 42 surrounding the shock absorber 4 by having a pin 43 on this bracket 44. The other end is connected to one end of a pair of links 41 with a pin 39 (FIG. 3), and the other end of the link 41 is connected with a pin 40 to the rod 38 of the actuator 50.
It is connected to. This actuator 50
is fixed to the outer cylinder 45 via a bracket 49.

As shown in FIG. 3, the actuator 50 has a piston 35 biased by a spring 37 fitted inside the cylinder 36, and the link 41 described above is connected to the rod 38 fixed to the piston 35. It's getting old. When pressurized oil is supplied to the end chamber 48 of the cylinder 36, the piston 35 is pushed against the force of the spring 37, and the pair of clamps 42 are closed to lock the shock absorber 4. The outer peripheral surface of the shock absorber 4 is preferably provided with a large number of annular grooves 4a or threaded grooves in order to securely engage the clamp 42. The inner surface of the clamp 42 is also provided with a groove that matches the annular groove 4a.

The actuator 50 that operates the clamp 42 and the actuator 9 that tilts the cab 3 are operated by an electric/hydraulic control circuit shown in FIG.
That is, when the hydraulic pump 52 is driven by the electric motor 53 when the cab 3 is tilted, the oil tank 51
The oil flows through the check valve 54, electromagnetic directional control valve 55, and throttle 5.
6 and the check valve 58 to one end chamber of the actuator 9, while the oil in the other end chamber is returned to the oil tank 51 through the throttle 57 and the electromagnetic directional control valve 55. Further, the pressure oil that has passed through the electromagnetic directional switching valve 55 passes through the electromagnetic switching valve 59 and is connected to the actuator 5.
0 cylinder 36.

When the pressure in the passage 74 exceeds a predetermined pressure, the check valve 58 releases its function as a check valve and the passage 7
3 and an end chamber of the actuator 9 are configured to communicate with each other. The electromagnetic switching valve 59 is configured such that when the electromagnetic coil is excited, a check valve is inserted into the passage 75 and connected.

The drive circuit for the electric motor 53, electromagnetic directional switching valve 55, and electromagnetic switching valve 59 includes a power battery 60, a fuse 61, a switch 63, a changeover switch 64, and a relay switch 62 consisting of a relay coil 62a and a contact piece 62b.

Next, the operation of the device of the present invention will be explained. First, when the cab 3 is in a normal state, that is, a state in which the vehicle can run, the clamp 42 is released in the state shown in FIG. The vibration of the cab 3 is suppressed against the vertical vibration of the vehicle frame 1 by the expansion and contraction of the suspension spring 6 as the link arm 5 swings about the tilt shaft 15 and the damper action of the shock absorber 4. At this time, the tilt lever 8 is attached to a link 2 that can be freely bent relative to the side frame 2 of the cab 3.
5 and 27, so it is not restricted.

Next, when tilting the cab 3 forward about the tilt shaft 15, first use the clamp 42 to prevent the shock absorber 4 from expanding or contracting, and then extend the actuator 9 to move the tilt lever 8 around the support shaft 17. When rotated counterclockwise about the center, the links 25 and 27 are folded and hit the bracket 29 of the side frame 2, and the cab 3 is pushed up. That is, when the switch 63 is closed in FIG. 4, the electromagnetic switching valve 59 is switched and the passage 75 is
A check valve is inserted into the At the same time, relay coil 6
2a is excited, the contact piece 62b is closed, and the electric motor 53
The hydraulic pump 52 is driven by. and,
When the changeover switch 64 is set to the illustrated state, the spool of the electromagnetic direction changeover valve 55 moves to the right, and the oil in the oil tank 51 is transferred to the passage 71 by the hydraulic pump 52.
It is forced into the end chamber 48 of the actuator 50 through the check valve 54, the electromagnetic directional control valve 55, the passage 73, the passage 75, and the check valve of the electromagnetic control valve 59, and the piston 35 is pushed against the force of the spring 37. .

Then, in FIG. 3, a pair of links 41 are bent together by the piston rod 38,
The clamps 42 are rotated about the pin 43 and engage the annular groove 4a to clamp the shock absorber 4. Therefore, the outer cylinder 45 and the shock absorber 4 are fixed, and the damper function of the shock absorber 4 is locked, so that relative displacement of the cab 3 in the vertical direction with respect to the vehicle frame 1 is prevented.

Delaying the operation of actuator 50, passage 73
Pressure oil enters the lower end chamber of the actuator 9 through the throttle 56 and the check valve 58, the piston rod is pushed up, and the tilt lever 8 is raised. The oil in the upper end chamber of the actuator 9 is transferred to the passage 7.
4, throttle 57, electromagnetic directional valve 55 and passage 7
2 and is returned to the oil tank 51.

When the cab 3 reaches a predetermined inclination using the tilt lever 8, when the switch 63 is opened, the electromagnetic directional control valve 55 is returned to the neutral position shown in FIG. 4, and the piston rod of the actuator 9 is in the extended state. Retained.

Next, when returning the cab 3 to its original state, the changeover switch 64 is switched as shown by the broken line and the switch 63 is closed. is maintained engaged with the shock absorber 4. Additionally, the spool of the electromagnetic directional control valve 55 moves to the left, and the oil from the hydraulic pump 52 flows through the passage 71, the check valve 54, the electromagnetic directional control valve 55, and the passage 7.
4 and the restrictor 57 to enter the upper end chamber of the actuator 9 and push down the piston rod.

At the same time, the check valve 58 is opened or brought into communication by the hydraulic pressure in the passage 74, so that the oil in the lower end chamber of the actuator 9 flows through the check valve 58, the passage 73, the throttle 56, the electromagnetic directional control valve 55, and the passage 72. The oil is returned to the oil tank 51 through the.

When the switch 63 is opened, the electric motor 53 is stopped, the electromagnetic directional control valve 55 is returned to the neutral position, and the electromagnetic directional control valve 59 is returned to the illustrated position, and the oil in the end chamber 48 of the actuator 50 is transferred to the electromagnetic directional control valve 59 and the passageway. 75, the electromagnetic directional control valve 55, and the passage 72 before being returned to the oil tank 51. At the same time, the piston rod 38 is returned by the force of the spring 37, and the clamp 4
2 is opened and the engagement with the shock absorber 4 is released.

In the above-described embodiment, the electromagnetic directional switching valve 55 may be manually operated, and an electromagnetic actuator may be used as the actuator.

[Effect of idea]

As described above, the present invention is equipped with a clamp that prevents the shock absorber from expanding and contracting, on the shock absorber connected between the vehicle frame and the cab.
When the cab is tilted, activating the clamp prevents the cab from rolling relative to the vehicle frame. especially,
Due to the fact that the engine is placed below the cab, even if the tilt lever is only placed on one side of the vehicle body, the force that pushes up the cab from the tilt lever acts on one side of the cab rather than the center. Therefore, the problem that the cab tilts to the other side and swings from side to side due to the deflection of the suspension spring is eliminated.

The clamp easily attaches to any conventional cab suspension system, minimizing added cost and providing stable and reliable operation.

[Brief explanation of the drawing]

Fig. 1 is a side view showing a tilt cab suspension system according to the present invention, Fig. 2 is a side view showing main parts of the shock absorber of the same device, Fig. 3 is a plan view of the same, and Fig. 4 is a side view showing the main part of the shock absorber of the device.
The figure is an electrical/hydraulic control circuit diagram of the device. 1... Vehicle frame, 3... Cab, 4... Shock absorber, 8... Tilt lever, 9... Tilt actuator, 15... Tilt shaft, 42... Clamp, 45... Outer cylinder, 50... Clamp Actuator, 52... Hydraulic pump, 53... Electric motor, 55... Solenoid directional switching valve, 59... Solenoid switching valve, 60... Power battery, 62... Relay switch, 63... Switch, 64... Switching Switch.

Claims (1)

[Scope of utility model registration request] 1. A suspension system for a tilt cab, characterized in that a shock absorber connected between a vehicle frame and a cab is provided with a clamp for preventing expansion and contraction of the shock absorber.