JPH07257129A - Wind-up restraining device for front suspension - Google Patents

Abstract

PURPOSE:To sufficiently prevent wind-up during braking, and to sufficiently ensure the stroke of a front wheel during normal running other than braking. CONSTITUTION:A wind-up restraining device comprises a wind-up stopper 42 for limiting the degree of deformation of a leaf spring 21, and an actuator 43 for extending the wind-up stopper to and from the leaf spring 21, and a solenoid valve and a switch for projecting the wind-up stopper 41 toward the leaf spring 21 during braking.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a windup suppressing device for a front suspension.

[0002]

2. Description of the Related Art In a vehicle such as a truck equipped with a leaf spring on a front suspension, there is a device for suppressing so-called wind-up, in which the leaf spring is twisted around an axle during braking (Actual No. Sho 63-2560).
No. 9, Japanese Utility Model Publication No. 63-151306,).

A conventional wind-up suppressing device for a front suspension is shown in FIG. 6, for example.

Explaining this, the front suspension includes a leaf spring 2 for suspending the front wheels 4 via a front axle tube 1, a shock absorber 8 for damping the vibration of the leaf spring 2, and a stabilizer for enhancing the roll rigidity of the vehicle. And 10.

As a windup suppressing device, a windup stopper 13 is attached to the frame 5 via a bracket 12. The wind-up stopper 13 made of an elastic material comes into contact with the rear portion of the leaf spring 2 to regulate the amount of bending of the leaf spring 2, so that the wind-up can be suppressed.

[0006]

By the way, in a four-wheel drive vehicle in which a propeller shaft, which is a drive system for front wheels, is arranged below an oil pan of an engine, a leaf spring winds up and a nose dive is applied during braking. Due to the synergistic effect of, the propeller shaft and the like may interfere with the oil pan.

However, by applying the above-mentioned conventional front suspension structure to a four-wheel drive vehicle, the amount of deflection of the leaf spring 2 regulated by the windup stopper 13 is prevented in order to prevent interference between the propeller shaft and the oil pan during braking. If is set to a sufficiently small value, the wind-up stopper will come into contact with the leaf spring during a large bounce even during normal driving other than braking, which causes a problem that the stroke amount of the front wheels becomes insufficient and the riding comfort deteriorates. .

The present invention has been made in view of the above problems, and an object thereof is to sufficiently prevent wind-up during braking and to secure a sufficient stroke amount of the front wheels during normal traveling other than during braking.

[0009]

A wind-up suppressing device for a front suspension according to claim 1 is restricted by a leaf spring for suspending a front wheel, a wind-up stopper for restricting a deflection amount of the leaf spring, and a wind-up stopper. An actuator that adjusts the amount of bending of the leaf spring, and a control unit that reduces the amount of bending of the leaf spring that is restricted by the windup stopper during braking.

A wind-up suppressing device for a front suspension according to a second aspect of the present invention is a leaf spring for suspending a front wheel, a front axle tube for supporting the front wheel with respect to the leaf spring, and a leaf positioned rearward of the vehicle from the front axle tube. A wind-up stopper that restricts the amount of deflection of the leaf spring by contacting the upper surface of the spring, and an actuator that advances and retracts the wind-up stopper with respect to the leaf spring,
And a control means for projecting the wind-up stopper toward the leaf spring during braking.

[0011]

In the wind-up suppressing device for the front suspension according to the first aspect of the present invention, the amount of deflection of the leaf spring regulated by the wind-up stopper is adjusted to be small during braking of the vehicle, and the propeller shaft on the front wheel side of a four-wheel drive vehicle is Interference with the oil pan is prevented.

During normal running of the vehicle, the amount of deflection of the leaf spring regulated by the wind-up stopper is greatly adjusted, and the stroke of the front wheel is sufficiently secured.

In a wind-up suppressing device for a front suspension according to a second aspect of the present invention, when the vehicle is braked, the wind-up stopper protrudes toward the leaf spring, and the upper surface of the rear portion of the leaf spring contacts the wind-up stopper, so that the leaf spring bends. The amount is restricted to a small amount to prevent the front wheel propeller shaft of a four-wheel drive vehicle from interfering with the oil pan.

During normal running of the vehicle, the wind-up stopper is held at a position distant from the leaf spring, and the amount of deflection of the leaf spring regulated by the wind-up stopper is increased to ensure a sufficient stroke amount of the front wheels. To be done.

[0015]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, 33 is a vehicle body frame provided in a four-wheel drive vehicle, 41 is an engine oil pan, and 31 is an engine oil pan.
Is a propeller shaft, 32 is a differential gear case, 20 is a front axle tube, and 37 is a front wheel. The propeller shaft 31 connects a transfer gear (not shown) provided at the rear of the engine and a differential gear case 32, and serves to transmit the rotational force of the engine to the front wheels 37. The propeller shaft 31 and the differential gear case 32 are arranged below the oil pan 41.

The front suspension of the vehicle is provided with a pair of left and right leaf springs 21 for suspending the front wheels 37 via the front axle tube 20 and shock absorbers 28 for damping the vibration of the leaf springs 21. The front axle tube 20 is coupled to the leaf spring 21 via a U bolt 39.

The leaf spring 21 is connected to the frame 33 at its front end through a bracket 34,
The rear end is connected to the shackle 35 via a bracket 36.

The frame 33 and the left and right leaf springs 2
A pair of wind-up stoppers 42 is provided between the front and rear of the front axle tube 20 so as to face the upper surface of the leaf spring 21. The wind-up stopper 42 regulates the amount of bending of the leaf spring 21 by abutting the upper surface of the leaf spring 21. The wind-up stoppers 42 are arranged facing each other at a position having a distance of about ¼ of the front-rear length from the rear end of each leaf spring 21.

As shown in FIG. 3, the windup stopper 42 is connected to the frame 33 via a hydraulic actuator 43.
The protrusion amount with respect to the frame 33 is changed by the expansion and contraction operation of the hydraulic cylinder 43.

The cylinder block 44 of the hydraulic actuator 43 has a joint frame 51 with respect to the frame 33, and is fixed via bolts inserted through the mounting holes 52 and 53. The hydraulic actuator 43 includes a cylinder 45 formed in a cylinder block 44 and a piston 46 slidably fitted in the cylinder 45, and a hydraulic chamber 47 is defined between the cylinder 45 and the piston 46.

A seat 49 is formed at the end of the piston 46 protruding from the cylinder 45, and a windup stopper 42 made of an elastic material such as rubber is fixed to the seat 49. When the piston 46 slides with respect to the cylinder 45, the windup stopper 42 causes the leaf spring 2 to move.
It comes to approach the upper surface of 1.

A return spring 50 is interposed between the cylinder block 44 and the piston 46. The return spring 50 biases the piston 46 in the contracting direction.

As shown in FIG. 4, the hydraulic chambers 47 of the left and right hydraulic actuators 43 communicate with the discharge side of the oil pump 56 via the electromagnetic valve 55. The solenoid valve 55 is switched to a position that guides the hydraulic oil discharged from the oil pump 56 to each hydraulic chamber 47 when the solenoid valve 55 is energized to extend each hydraulic actuator 43, and the hydraulic oil in each hydraulic chamber 47 is stored in the tank 57 when the hydraulic actuator 47 is not energized. The hydraulic actuator 43 is contracted by the reaction force of the return spring 50.

In this embodiment, the oil pump 56 is
Although it is provided exclusively for the wind-up suppressing device, it may be used also as an oil pump provided in the power steering device.

In FIG. 4, reference numeral 58 is a brake pedal which is depressed by the driver during braking, and 59 is a brake switch which is closed in conjunction with depression of the brake pedal 58. The solenoid valve 55 is connected to the battery 61 via a brake switch 59.

With the above construction, the operation will be described below.

When the vehicle is being braked, the leaf spring 21 is attached to the front axle tube 20 as shown in FIG.
As shown by the arrow in the figure, the load that tries to rotate and the load that tries to sink the front part of the vehicle work, and the latter half of the leaf spring 21 tends to bend largely upward. The propeller shaft 31 is located below the engine oil pan 41.
In the four-wheel drive vehicle in which is arranged, if the leaf spring 21 is excessively bent during deceleration, the propeller shaft 31 and the like may interfere with the oil pan 41.

When the vehicle is being braked, the brake switch 59 is closed as the brake pedal 58 is depressed,
The solenoid valve 55 is switched to a position where the hydraulic oil discharged from the oil pump 56 is guided to each hydraulic chamber 47, and each hydraulic actuator 43 is extended. As a result, the wind-up stopper 42 is held at a position closer to the leaf spring 21, the amount of deflection of the leaf spring 21 regulated by the wind-up stopper 42 is reduced, and the propeller shaft 31 and the like collide with the oil pan 41. And prevents the nose dive of the vehicle.

During normal running of the vehicle, the brake switch 5
9 is open, the solenoid valve 55 is switched to a position where the hydraulic oil in each hydraulic chamber 47 is returned to the tank 57, and each hydraulic actuator 43 is contracted. As a result, the wind-up stopper 42 is held at a position away from the leaf spring 21, and the amount of deflection of the leaf spring 21 regulated by the wind-up stopper 42 is increased to ensure a sufficient stroke amount of the front wheel 37. It is possible to prevent the riding comfort from being impaired.

Next, another embodiment shown in FIG. 5 is to drive the wind-up stopper by utilizing the hydraulic pressure of the brake device. It should be noted that the same reference numerals are used for the portions corresponding to those in FIG.

In the figure, 61 is a break valve, 62 and 63 are wheel cylinders for front and rear wheels, 64 is an air booster, and 65 is an air booster.
Is an air reservoir, 66 is an air compressor, and 67 is a brake fluid reservoir.

A brake valve 61 that operates when the vehicle is braked.
A part of the hydraulic oil sent to the wheel cylinders 62, 63 of the front and rear wheels via the is sent to the wind-up stopper 42. As a result, the wind-up stopper 42 is held at a position closer to the leaf spring 21, the amount of deflection of the leaf spring 21 regulated by the wind-up stopper 42 is reduced, and the propeller shaft 31 and the like collide with the oil pan 41. And prevents the nose dive of the vehicle.

[0034]

As described above, the wind-up suppressing device for the front suspension according to claim 1 has a leaf spring for suspending the front wheel, a wind-up stopper for regulating the amount of deflection of the leaf spring, and a wind-up stopper. Since the actuator for adjusting the amount of deflection of the leaf spring is provided and the control means for reducing the amount of deflection of the leaf spring regulated by the windup stopper at the time of braking, windup at the time of braking is sufficiently suppressed. It is possible to prevent the front wheel side propeller shaft and the like of a wheel drive vehicle from interfering with the oil pan, and at the same time, to secure a sufficient stroke amount of the front wheels at the time of normal traveling other than during braking, thereby preventing the riding comfort from being impaired.

A wind-up suppressing device for a front suspension according to a second aspect of the present invention is a leaf spring for suspending a front wheel, a front axle tube for supporting the front wheel with respect to the leaf spring, and a leaf located rearward of the vehicle from the front axle tube. A wind-up stopper that restricts the amount of bending of the leaf spring by contacting the upper surface of the spring, and an actuator that moves the wind-up stopper forward and backward with respect to the leaf spring,
Since the wind-up stopper protrudes toward the leaf spring during braking, the wind-up stopper comes into contact with the upper surface of the rear portion of the leaf spring during braking of the vehicle, so that the amount of deflection of the leaf spring is restricted to a small amount, and the wind spring is reliably controlled. Operability is obtained.

[Brief description of drawings]

FIG. 1 is a side view of a front suspension showing an embodiment of the present invention.

FIG. 2 is a side view of the front suspension showing an operating state of the windup stopper.

FIG. 3 is a sectional view of the windup stopper.

FIG. 4 is a hydraulic circuit diagram of the windup suppressing device.

FIG. 5 is a configuration diagram of a windup suppressing device showing another embodiment.

FIG. 6 is a side view of a front suspension showing a conventional example.

[Explanation of symbols]

 20 Front Axle Tube 21 Leaf Spring 31 Propeller Shaft 42 Windup Stopper 43 Hydraulic Actuator 55 Solenoid Valve 56 Oil Pump 58 Brake Pedal 59 Brake Switch

Claims (2)

[Claims] 1. A leaf spring for suspending a front wheel, a wind-up stopper for regulating the amount of deflection of the leaf spring, an actuator for adjusting the amount of deflection of the leaf spring regulated by the wind-up stopper, and a wind-up stopper for braking. A wind-up suppressing device for a front suspension, comprising: a control unit that reduces the amount of deflection of a leaf spring that is restricted. 2. A leaf spring that suspends the front wheel, a front axle tube that supports the front wheel with respect to the leaf spring, and a leaf spring that is located rearward of the vehicle with respect to the front axle tube and is in contact with the upper surface of the leaf spring. A front suspension characterized by comprising a wind-up stopper that regulates the amount, an actuator that moves the wind-up stopper forward and backward with respect to the leaf spring, and control means that causes the wind-up stopper to project toward the leaf spring during braking. Windup suppression device.