Hydraulic engine mount with air bellows tuning

• US 4,869,477 A
• Filed: 09/06/1988
• Issued: 09/26/1989
• Est. Priority Date: 09/06/1988
• Status: Expired due to Term

• Current Assignee: General Motors Auto OOO (General Motors Company)
• Original Assignee: General Motors Corporation (General Motors Company)
• Inventors: Hoying, John F., Smith, Stanley E.
• Primary Examiner(s): Reger, Duane A.
• Application Number:
  US07/240,668
• Time in Patent Office: 385 Days
• Field of Search: 248/562, 267/140.1, 267/218, 267/219, 280/706, 280/707
• US Class Current: 267/140.14
• CPC Class Codes: F16F 13/20 characterised by comprising also a pneumatic spring F16F13/22, F16F13/26 take precedence
• CPC Class Codes: F16F 13/26 characterised by adjusting or regulating devices responsive to exterior conditions F16F13/101 takes precedence

Abstract

A hydraulic mount assembly is disclosed having a partition forming two hydraulic chambers and including a damping decoupler. A primary chamber is formed by an elastomeric member and a secondary chamber by a resilient diaphragm. During dynamic loading of the mount, fluid passes through an orifice between the two chambers of the mount causing expansion and contraction of the diaphragm. An expandable, pneumatic bellows is mounted within the primary chamber. A vent tube provides controlled fluid communication between the bellows and the atmosphere to provide a relatively soft mount for engine isolation. Air entry into the bellows is induced by the built-in spring memory of the bellows causing expansion. Air may be removed or partially removed from the bellows by an external vacuum source, causing a negative pressure and contraction. By controlling bellows expansion and contraction in this manner, the dynamic rate of the mount assembly may be selectively reduced at higher vibration frequencies; that is, those over 20 Hz. An assist spring may be provided in the bellows. Further, by evacuating the bellows, a relatively hard mount with standard operating parameters may be provided; i.e. a mount having relatively high damping and high rate for better control under extreme driving conditions. A control circuit with on-board transducers is provided to monitor vehicle operating and road conditions and modulate the pressure by controlling venting of the bellows and the vacuum in the bellows for maximum operating efficiency.

Claims

1. A hydraulic mount assembly for a vehicle, comprising:

a pair of mounting members;

a hollow body connected to said mounting members;

an elastic diaphragm closing said hollow body and forming therewith a closed cavity that is filled with hydraulic fluid;

means for partitioning said cavity into a primary chamber and a secondary chamber enclosed by said diaphragm;

an office in said partitioning means connecting said chambers so as to effect damping; and

a self expanding pneumatic bellows mounted within said primary chamber for controlling the damping and the dynamic rate of said mount assembly on the vehicle at relatively high frequencies of vibration for tuning said mount assembly, said bellows having a self expanding force sufficient to overcome a counteracting elastic force of said diaphragm.

2. A hydraulic mount assembly for a vehicle, comprising:

a pair of mounting members;

a hollow elastic body connected to said mounting members;

an elastic diaphragm closing said hollow body and forming therewith a closed cavity that is filled with hydraulic fluid;

means for partitioning said cavity into a primary chamber and a secondary chamber enclosed by said diaphragm;

an orifice in said partitioning means connecting said chambers so as to effect damping;

a self expanding elastic bellows mounted within said primary chamber and filled with a compressible fluid, said bellows having a self expanding elastic force sufficient to overcome a counteracting elastic force of said diaphragm;

means for positively limiting the expansion of said self expanding bellows;

means for sensing vehicle operating conditions and resulting vibrations; and

means for controlling expansion of said bellows against the elastic force of said diaphragm in response to said means for sensing vehicle operating conditions, whereby damping and dynamic rate characteristics of said mount assembly may be tuned as desired especially for relatively high frequency vibrations.

3. A hydraulic mount assembly for a vehicle, comprising:

a pair of mounting members;

a hollow elastic body connected to said mounting member;

an elastic diaphragm closing said hollow body and forming therewith a closed cavity that is filled with hydraulic fluid;

means for partitioning said cavity into a primary chamber and a secondary chamber enclosed by said diaphragm;

an orifice in said partitioning means connecting said chambers so as to effect damping;

an expandable, elastic bellows mounted within said primary chamber and filled with a compressible fluid;

the elastic force of said bellows being sufficient to provide self-inflation against the elastic force of said diaphragm on said hydraulic fluid in said cavity when said secondary chamber is expanded;

means for providing fluid communication between said bellows and the atmosphere;

valve means for selectively opening and closing said means for providing fluid communication with the atmosphere;

vacuum supply means connected to said expandable bellows to selectively reduce the fluid pressure within said bellows;

means for sensing vehicle operating conditions and resulting vibrations; and

means for selectively controlling said valve means and said vacuum supply means in response to said means for sensing vehicle operating conditions whereby the damping and dynamic rate characteristics of said mount assembly may be tuned as desired especially for relatively high frequency vibrations.