Seat suspension mechanism

Patent metadata

Field	Value
Publication number	US-12269382-B2
Application number	US-202017770790-A
Country	US
Kind code	B2
Filing date	Oct 22, 2020
Priority date	Oct 22, 2019
Publication date	Apr 8, 2025
Grant date	Apr 8, 2025

Abstract

A body weight adjustment mechanism for automatic adjustment to a balanced point is provided to improve vibration absorption characteristics and impact absorption characteristics. A torsion angle of a lower frame-side torsion bar when an upper frame is at a balanced point is found in advance, a torsion angle of the lower frame-side torsion bar in a state in which a person is seated is detected, the detected torsion angle is compared with the aforesaid balanced point torsion angle, a control signal is sent to an elastic force adjusting unit, and torsion angles of upper frame-side torsion bars are adjusted so that the torsion angle of the lower frame-side torsion bar becomes equal to the balanced point torsion angle. The upper frame can be set to an appropriate position in an initial state and a static state in which a person is seated and vibration and impact absorption characteristics are improved.

First claim

The invention claimed is:

1. A seat suspension mechanism comprising: an upper frame and a lower frame that are supported so as to be capable of a separating and approaching operation relative to each other, with a link mechanism therebetween; and a spring mechanism which elastically biases the upper frame,
wherein the spring mechanism includes:
a first spring part which biases the upper frame in a direction in which the upper frame separates from the lower frame; and
a second spring part which, when the upper frame is in a predetermined up-down movement range including a balanced point, exhibits a spring characteristic of biasing the upper frame in a direction in which the upper frame approaches the lower frame, to create a constant load spring characteristic by being combined with the first spring part,
the seat suspension mechanism further comprising a body weight adjustment mechanism which adjusts a position of the upper frame to the balanced point in a state in which a person is supported,
wherein the first spring part includes a lower frame-side torsion bar which is connected to the lower frame and is twisted by movement of the link mechanism and an upper frame-side torsion bar which is connected to the upper frame and is twisted by the movement of the link mechanism,
wherein the body weight adjustment mechanism includes:
an elastic force adjusting unit which is connected to the upper frame-side torsion bar and adjusts the position of the upper frame by twisting the upper frame-side torsion bar;
a torsion angle detection sensor which detects a torsion angle of the lower frame-side torsion bar; and
a control unit which compares the torsion angle of the lower frame-side torsion bar detected by the torsion angle detection sensor with a balanced point torsion angle that the lower frame-side torsion bar has when the upper frame is at the balanced point, and outputs, to the elastic force adjusting unit, a control signal instructing to twist the upper frame-side torsion bar by a predetermined amount to make the torsion angle of the lower frame-side torsion bar agree with the balanced point torsion angle, and
wherein a damper is suspended between the lower frame and the upper frame, and a movement zone of a piston in a cylinder of the damper corresponding to the predetermined up-down movement range including the balanced point when the upper frame moves up and down relative to the lower frame is free running zone where a damping force in the free running zone is lower compared with a damping force in a zone other than the free running zone.

2. The seat suspension mechanism according to claim 1 , wherein the cylinder is a dual structure which includes an outer fixed cylinder and an inner movable cylinder, the outer fixed cylinder has, at their longitudinal-direction ends, stopper portions, and the inner movable cylinder, which is shorter in the axial-direction length than the outer fixed cylinder, is movable until longitudinal-direction ends of the inner movable cylinder abut on the stopper portions,
the piston is slidable in the inner movable cylinder and has a string portion formed by winding a linear member to which a viscous fluid is adhered,
a low-friction member is interposed between the inner movable cylinder and the outer fixed cylinder, so that a frictional force between the inner movable cylinder and the outer fixed cylinder becomes relatively smaller than a frictional force generated by between the inner movable cylinder and the string portion of the piston,
a range where the piston together and the inner movable cylinder relatively move together in the outer fixed cylinder, until the longitudinal-direction ends of the inner movable cylinder abut on the stopper portions, is the free running zone, and
after the longitudinal-direction ends of the inner movable cylinder abut on the stopper portions, the inner movable cylinder cannot move and only the piston slides in the inner movable cylinder, and the friction damping force and viscous damping force of the viscous fluid act between the piston and the inner movable cylinder.

3. The seat suspension mechanism according to claim 1 , wherein the second spring part includes a magnetic spring which includes a stationary magnet and a movable magnet whose position relative to the stationary magnet changes in accordance with the up-down movement of the upper frame relative to the lower frame, the magnetic spring exhibiting a nonlinear characteristic of changing in spring constant according to the position of the movable magnet relative to the stationary magnet.

4. The seat suspension mechanism according to claim 3 , wherein the second spring part further includes an auxiliary spring mechanism including between the lower frame and the upper frame: a pantograph link including an upper link and a lower link whose connection point is displaced in a front-rear direction; and a tensile coil spring suspended on the pantograph link in the front-rear direction, the auxiliary spring mechanism exhibiting a spring characteristic of biasing the upper frame downward when the upper frame is in the predetermined up-down movement range including the balanced point.

Assignees

• Delta Kogyo Co

Inventors

• Fujita Etsunori
• Makita Soichi
• Maeda Shinichiro
• MASUMURA Shogo
• Oka Masaru

Classifications

• F16F15/03

  using {magnetic or} electromagnetic means (F16F9/53, {F16F15/005} take precedence) · CPC title

• F16F6/00

  Magnetic springs {(magnetic spring arrangements for the suppression of vibration in systems F16F15/03)}; Fluid magnetic springs {, i.e. magnetic spring combined with a fluid} · CPC title

• F16F1/06

  with turns lying in cylindrical surfaces · CPC title

• B60N2/682

  Joining means · CPC title

• B60N2/90

  Details or parts not otherwise provided for · CPC title