JP2005106192A - Cylindrical engine mount - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylindrical engine mount capable of reducing bad influence to acceleration noise of a vehicle due to resonance of a first bracket, while avoiding increase of the number of structural parts items and a big rise of the cost. <P>SOLUTION: The cylindrical engine mount is formed of a spindle member 1 held by a pair of arm parts 71 of the first bracket 7 in both ends thereof and fixed to a fitting part of an engine E, an outer cylindrical member 2 concentrically arranged outside the spindle member 1 and held by a second bracket 8 in the peripheral surface thereof and fixed to a fitting part of a car body S, a rubber vibration control structure 3 interposed between the spindle member 1 and the outer cylindrical member 2, and a pair of ring-like rubber stoppers 4 fitted on the periphery of both ends of the spindle member 1 to regulate relative displacement of the spindle member 1 and the outer cylindrical member 2 in the axial direction. In each of the rubber stoppers 4, a ring-like mass member 5 is embedded in a part separated from the inner peripheral surface by the predetermined distance outward in the radial direction, and a dynamic damper is formed by the mass member 5 and a rubber spring of a support part 42 for supporting the mass member 5 on the inner peripheral side of the mass member 5. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a cylindrical engine mount that provides vibration-proof support for an engine mounted on a vehicle.

  2. Description of the Related Art Conventionally, in a vehicle equipped with an engine that is a vibration generation source, an engine mount is used so as to support the vibration isolation of the engine when the engine is attached to the body frame. As such an engine mount, for example, a cylindrical engine mount as disclosed in Patent Document 1 is known.

  This cylindrical engine mount is formed by interposing a main shaft member, an outer cylinder member coaxially disposed on the outer side of the main shaft member, and between the main shaft member and the outer cylinder member. A substantially cylindrical rubber elastic body to be connected, and a pair of ring-plate-shaped rubber stoppers that are fitted and held on the outer periphery of both ends of the main shaft member and restrict the relative displacement in the axial direction of the main shaft member and the outer cylinder member Has been.

  In this cylindrical engine mount, both ends of the main shaft member are clamped by a pair of arm portions of the first bracket and fixed to either the vehicle body side or the engine side mounting portion, and the outer cylinder member is connected to the second bracket. It is attached by being press-fitted and held in the mounting hole and fixed to the other attachment portion on the vehicle body side or the engine side.

  When vibration generated from the engine is input to the cylindrical engine mount mounted in this way, the elastic rubber body is elastically deformed, so that vibration in a predetermined frequency range (about 100 to 500 Hz) is reduced. The Further, when axial vibration is input to the cylindrical engine mount, the interference sound generated by the outer cylindrical member and the first bracket is prevented by the rubber stoppers disposed at both ends of the main shaft member. At the same time, excessive relative displacement between the main shaft member and the outer cylinder member is restricted, so that excessive deformation of the rubber elastic body is prevented, thereby improving durability.

  By the way, when the cylindrical engine mount is mounted using the first bracket that sandwiches and supports the both ends of the main shaft member with the pair of arms as described above, vibration from the engine side is the first. The first bracket is likely to resonate when transmitted to the bracket. In particular, it is considered that when the first-order mode bending resonance occurs, the displacement becomes the largest, and accordingly, the displacement of the main shaft member sandwiched between the pair of arms of the first bracket also becomes larger. When resonance occurs in the first bracket in this way, the vehicle acceleration noise is adversely affected, and the vehicle acceleration noise level is greatly deteriorated.

  Therefore, as one of the countermeasures, there is a method of changing the eigenvalue of the first bracket by increasing the thickness of the first bracket or by providing a rib on the arm portion of the first bracket. It is difficult to set the eigenvalue to a region that does not affect vehicle acceleration noise (400 to 600 Hz on the vehicle body side and 600 Hz or more on the engine side) because the weight of the first bracket is significantly increased and the size is increased.

As another countermeasure, there is a method of using a dynamic damper as disclosed in, for example, Patent Documents 2 and 3 for the first bracket. In this case, the dynamic damper tuned to the eigenvalue of the first bracket is installed in the first bracket, so that the resonance of the first bracket is suppressed and the vehicle acceleration noise is not adversely affected. However, in the case of this method, since a dynamic damper is added, the number of components increases correspondingly, resulting in a significant increase in cost.
Japanese Utility Model Publication No. 60-118047 Japanese Utility Model Publication No. 4-4541 JP-A-8-109948

  The present invention has been made in view of the above circumstances, and is a cylindrical type that can reduce the adverse effects on the vehicle acceleration noise due to the resonance of the first bracket while avoiding an increase in the number of components and a significant increase in cost. Providing an engine mount is a problem to be solved.

  A cylindrical engine mount of the present invention that solves the above problems includes a main shaft member that is clamped at both ends by a pair of arm portions of a first bracket and fixed to either one of a vehicle body side and an engine side mounting portion, and the main shaft An outer cylindrical member that is disposed substantially coaxially at a distance from the outside of the member, has an outer peripheral surface held by a second bracket, and is fixed to either the vehicle body side or the engine side mounting portion; and the main shaft member; A rubber vibration isolating structure that is interposed between the outer cylinder member and integrally connects the two, and is fitted and held on the outer periphery of both ends of the main shaft member, so that the main shaft member and the outer cylinder member are arranged in the axial direction. A cylindrical engine mount comprising a pair of ring-shaped rubber stoppers for regulating relative displacement, wherein at least one of the rubber stoppers is located at a portion spaced a predetermined distance radially outward from the inner peripheral surface. Ring-shaped mass member It is set, and characterized in that the dynamic damper is formed by the rubber spring and the mass member of the support portion for supporting the mass member at the inner peripheral side of the mass member.

  In the cylindrical engine mount of the present invention, when the first bracket resonates when vibration is transmitted from the engine side to the first bracket, the main shaft member also resonates with the first bracket. Due to the resonance of the main shaft member, the mass member embedded in the rubber stopper fitted and held on the outer periphery of both ends of the main shaft member resonates via the rubber spring of the support portion of the rubber stopper, thereby functioning as a dynamic damper. Thus, resonance of the main shaft member and the first bracket is suppressed. Therefore, the adverse effect on the vehicle acceleration noise due to the resonance of the first bracket is reduced.

  In addition, since the dynamic damper in the present invention is formed on the rubber stopper disposed on the outer periphery of both ends of the main shaft member, the dynamic damper is at the position where the damper effect is most exerted with respect to the eigenvalue of the primary mode of the first bracket. Therefore, the resonance of the first bracket can be effectively suppressed.

  In addition, since the dynamic damper according to the present invention is formed using existing rubber stoppers provided at both ends of the main shaft member, an increase in the number of components is avoided, and a significant increase in cost is also avoided. .

  Therefore, the cylindrical engine mount of the present invention can reduce the adverse effect on the vehicle acceleration noise due to the resonance of the first bracket while avoiding an increase in the number of components and a significant increase in cost.

  In the cylindrical engine mount of the present invention, it is preferable that the resonance frequency of the dynamic damper formed on the rubber stopper is tuned according to the eigenvalue of the first bracket. If it does in this way, resonance of the 1st bracket can be controlled more certainly. The resonance frequency of the dynamic damper is basically determined by the spring constant in the radial direction of the support portion of the rubber stopper and the mass of the mass member.

  In the cylindrical engine mount of the present invention, it is preferable that the outer diameter of the mass member is smaller than the inner diameter of the outer cylinder member. In this way, it is possible to make it difficult for the mass member embedded in the rubber stopper and the outer cylinder member to interfere when axial vibration is input to the cylindrical engine mount. Thereby, when the end surface of the outer cylinder member comes into contact with the rubber stopper, it is difficult for the rubber stopper to be damaged, and durability can be improved. In addition, the outer diameter of the mass member is set to the inner diameter of the outer cylinder member so that the mass member and the outer cylinder member do not interfere when the axial vibration and the vibration perpendicular to the axis are simultaneously input to the cylindrical engine mount. If it is made sufficiently small, the dynamic damper can always function.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a plan view partially showing a mounting state of the tubular engine mount according to the present embodiment, and FIG. 2 is a sectional view along the axial direction of the tubular engine mount according to the present embodiment.

  As shown in FIG. 2, the cylindrical engine mount of the present embodiment includes a main shaft member 1, an outer cylinder member 2 that is coaxially arranged at a distance from the outer side of the main shaft member 1, and the main shaft member 1 and the outer cylinder. The rubber vibration isolating structure 3 that is interposed between the members 2 and integrally connected to each other, and the outer periphery of both ends of the main shaft member 1 are fitted and the mass members 5 and 5 are embedded, so that dynamic It is comprised from a pair of rubber stoppers 4 and 4 in which a damper is formed.

  The main shaft member 1 is formed in a thick and straight cylindrical shape from an iron-based metal.

  The outer cylinder member 2 is formed of a ferrous metal in a thin cylindrical shape that is thinner than the main shaft member 1. The outer cylindrical member 2 has an inner diameter that is larger than the outer diameter of the main shaft member 1 by a predetermined dimension, and has an axial length that is about 2/3 of the axial length of the main shaft member 1. A seal rubber layer 21 is fixed to the inner peripheral surface of the outer cylinder member 2 so as to cover the entire area of the inner peripheral surface. The outer cylindrical member 2 is arranged in a state slightly decentered from the main shaft member 1 at the center portion in the axial direction on the outer peripheral side of the main shaft member 1. When the cylindrical engine mount is disposed so as to support the vibration isolation of the engine, the rubber vibration isolation structure 3 is elastically deformed by the load of the engine and the main shaft member as shown in FIG. 1 and the outer cylinder member 2 become substantially coaxial. That is, FIG. 2 shows a state in which a shared engine load is applied to the cylindrical engine mount.

  The rubber vibration-proof structure 3 is formed in a substantially cylindrical shape by vulcanizing and molding a rubber material between the main shaft member 1 and the intermediate cylindrical metal fitting 32 arranged in a slightly eccentric state on the outer peripheral side of the main shaft member 1. A rubber elastic body 31 is provided. On the outer peripheral surface of the rubber elastic body 31, there are provided two concave portions that open to two window portions formed in the intermediate cylinder fitting 32. The openings of the two recesses are sealed with the seal rubber layer 21 of the outer cylinder member 2 coaxially disposed on the outer peripheral side of the intermediate cylinder fitting 32, whereby the main liquid chamber 33 and the sub liquid chamber 34 are separated. Is formed. An incompressible liquid 37 is sealed in the main liquid chamber 33 and the sub liquid chamber 34. Further, in the main liquid chamber 33 and the sub liquid chamber 34, a ring-shaped resin stopper 35 that restricts the relative displacement in the radial direction between the main shaft member 1 and the outer cylinder member 2 is disposed. An orifice passage 36 that communicates the main liquid chamber 33 and the sub liquid chamber 34 is provided on the outer peripheral portion of the resin stopper 35.

  That is, the rubber vibration isolating structure 3 absorbs vibrations in a predetermined high frequency range (about 100 to 500 Hz) through elastic deformation of the rubber elastic body 31 and is connected to the main liquid chamber 33 through the orifice passage 36. Based on the liquid column resonance action of the liquid 37 flowing between the sub liquid chambers 34, it is configured to absorb vibrations in a low frequency range (about 8 to 15 Hz) such as an engine shake.

  The rubber stoppers 4, 4 are formed in a ring plate shape by vulcanization molding of a rubber material, have an inner diameter slightly smaller than the outer diameter of the main shaft member 1, and are larger than the outer diameter of the outer cylinder member 2. It has a slightly larger outer diameter. The rubber stoppers 4 and 4 are provided with ring-shaped stopper portions 41 and 41 that bulge toward one side in the axial direction and are formed thicker than the inner peripheral side portion. The rubber stoppers 4, 4 are fitted and held by press-fitting their center holes to the outer periphery of both end portions of the main shaft member 1, and the stopper portions 41, 41 provided at the outer peripheral side end portions are the outer cylinder member 2. It is arrange | positioned so that it may oppose with a predetermined distance and the end surface of this.

  Mass members 5 and 5 each having a predetermined mass formed in a ring shape having a rectangular cross section are embedded in portions of the rubber stoppers 4 and 4 that are separated from the inner peripheral surface of the rubber stoppers 4 and 4 by a predetermined distance in the radial direction. Yes. The mass members 5, 5 have an outer diameter sufficiently smaller than the inner diameter of the outer cylinder member 2, and are embedded in the inner peripheral portions of the rubber stoppers 4, 4 and embedded in the stopper portions 41, 41. Not. Since the mass members 5 and 5 are embedded in this manner, each mass member 5 is a portion between the inner peripheral surface of each rubber stopper 4 and 4 and the inner peripheral surface of each mass member 5 and 5. A dynamic damper is formed by the rubber springs of the support portions 42 and 42 that support the mass members 5 and 5 and the mass members 5 and 5 on the inner peripheral side of the mass member 5.

  The resonance frequency (fn) of the dynamic damper is determined based on the spring constant in the radial direction of the support portions 42 and 42 and the mass of the mass members 5 and 5. In the present embodiment, the resonance frequency (fn) of the dynamic damper is tuned according to the natural value of the first bracket 7 that holds both ends of the main shaft member 1 with a pair of arms. In addition, the spring constant in the radial direction of the support portions 42, 42 is larger than the spring constant in the radial direction of the rubber elastic body 31 of the rubber vibration-proof structure 3. Moreover, since the mass of the mass member used for the dynamic damper can be selected from various masses in relation to the resonance frequency (fn) and the spring constant, it is generally set in the range of 50 g to 1 kg. In this embodiment, the mass of each mass member 5 and 5 is set in the range of 100 to 400 g.

  As shown in FIG. 1, the cylindrical engine mount of the present embodiment configured as described above has a pair of arms 71 and 71 that cantilever support both ends of the main shaft member 1. Mounting between the mounting portion on the vehicle body S side and the mounting portion on the engine E side using the first bracket 7 having a cylindrical shape and the second bracket 8 having the cylindrical portion 81 that holds the outer peripheral surface of the outer cylindrical member 2. It is done. That is, in the present embodiment, both ends of the main shaft member 1 are sandwiched between the pair of arm portions 71 and 71 of the first bracket 7 via the mounting bolts 73 and nuts 74 inserted into the shaft holes of the main shaft member 1. The outer cylinder member 2 is fixed to the mounting portion on the vehicle body S side in a state where the outer cylindrical member 2 is press-fitted and held in the cylindrical portion 81 of the second bracket 8. .

  When vibration generated from the engine E is input to the cylindrical engine mount attached in this way, the rubber elastic body 31 of the rubber vibration-proof structure 3 is elastically deformed, and vibration in a predetermined high frequency range is generated. Reduced. Further, vibration in the low frequency region such as engine shake is effectively reduced by the liquid column resonance action of the liquid 37 flowing between the main liquid chamber 33 and the sub liquid chamber 34 via the orifice passage 36.

  When axial vibration is input to the cylindrical engine mount, the outer cylindrical member 2 and the first bracket 7 generate the rubber stoppers 4 and 4 respectively disposed at both ends of the main shaft member 1. Interference noise is prevented and excessive deformation of the main shaft member 1 and the outer cylinder member 2 is restricted, thereby preventing excessive deformation of the rubber elastic body, thereby improving durability.

  Further, when the first bracket 7 resonates when vibration is transmitted from the engine E side to the first bracket 7, the main shaft member 1 resonates together with the first bracket 7. Due to the resonance of the main shaft member 1, the mass members 5, 5 embedded in the rubber stoppers 4, 4 fitted and held on the outer periphery of both ends of the main shaft member 1 are connected to the support portions 42, 42 of the rubber stoppers 4, 42. By resonating through the rubber spring, a function as a dynamic damper is exhibited, whereby the resonance of the main shaft member 1 and the first bracket 7 is suppressed. Therefore, adverse effects on vehicle acceleration noise due to resonance of the first bracket 7 are reduced.

  Since the dynamic damper is formed on the rubber stoppers 4 and 4 disposed on the outer periphery of both ends of the main shaft member 1, the dynamic damper exhibits the most damper effect with respect to the eigenvalue of the primary mode of the first bracket 7. Therefore, the resonance of the first bracket 7 can be effectively suppressed.

  Further, since this dynamic damper is formed using the existing rubber stoppers 4 and 4 provided at both ends of the main shaft member 1, an increase in the number of components is avoided, and a significant increase in cost is also avoided. Is done.

  As described above, in the cylindrical engine mount of the present embodiment, the mass members 5 and 5 are embedded in predetermined portions of the rubber stoppers 4 and 4, and the mass members 5 and 5 are attached to the inner peripheral side of the mass members 5 and 5. Since the dynamic damper is formed by the rubber springs of the supporting portions 42 and 42 to be supported and the mass members 5 and 5, the increase in the number of components and the significant increase in cost are avoided, and the first bracket 7 is resonated. The adverse effect on vehicle acceleration noise can be reduced.

  Further, in the cylindrical engine mount of the present embodiment, the resonance frequency of the dynamic damper formed on the rubber stoppers 4 and 4 is tuned according to the eigenvalue of the first bracket 7, so that the resonance of the first bracket 7 is made. It can suppress more reliably.

  Further, in the cylindrical engine mount of the present embodiment, the outer diameter of the mass members 5 and 5 is sufficiently smaller than the inner diameter of the outer cylindrical member 2, so that the vibration in the axial direction relative to the cylindrical engine mount is reduced. Since the mass members 5, 5 embedded in the rubber stoppers 4, 4 and the outer cylinder member 2 can be made difficult to interfere with each other, the rubber stoppers 4, 4 are hardly damaged and are durable. It is possible to improve the performance. It is also possible for the dynamic damper to always function.

  In this embodiment, the mass members 5 and 5 are embedded in both rubber stoppers 4 and 4 so as to form dynamic dampers respectively. However, the mass member 5 is embedded only in one rubber stopper 4. Thus, a dynamic damper may be formed.

  Further, in the present embodiment, the first bracket 7 is fixed to the mounting portion on the engine E side, and the second bracket 8 is fixed to the mounting portion on the vehicle body S side. 7 may be fixed to the mounting portion on the vehicle body S side, and the second bracket 8 may be fixed to the mounting portion on the engine E side.

  Further, the rubber vibration isolating structure 3 in the present embodiment is of a liquid-filled type and is configured to reduce vibration in a low frequency range. You may change into what is comprised only with the elastic body 31. FIG.

It is a top view which shows the attachment state of the cylindrical engine mount which concerns on embodiment of this invention in a partial cross section. It is sectional drawing which follows the axial direction of the cylindrical engine mount which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Main shaft member 2 ... Outer cylinder member 3 ... Rubber vibration-proof structure 4 ... Rubber stopper 5 ... Mass member 7 ... 1st bracket 8 ... 2nd bracket 21 ... Sealing rubber layer 31 ... Rubber elastic body 32 ... Intermediate cylinder metal fitting 33 ... Main liquid chamber 34 ... Sub liquid chamber 35 ... Resin stopper 36 ... Orifice passage 37 ... Liquid 41 ... Stopper portion 42 ... Support portion 71 ... Arm portion 73 ... Mounting bolt 74 ... Nut 81 ... Cylindrical portion E ... Engine S ... Vehicle body

Claims (4)

A main shaft member sandwiched at both ends by a pair of arm portions of the first bracket and fixed to either the vehicle body side or the engine side mounting portion;
An outer cylinder member that is disposed substantially coaxially at a distance from the outside of the main shaft member, has an outer peripheral surface held by a second bracket, and is fixed to either the vehicle body side or the engine side mounting portion;
A rubber vibration isolating structure that is interposed between the main shaft member and the outer cylinder member and integrally couples the two;
A cylindrical engine mount provided with a pair of ring-shaped rubber stoppers that are fitted and held on the outer periphery of both ends of the main shaft member and restrict relative displacement in the axial direction of the main shaft member and the outer cylinder member,
At least one of the rubber stoppers is embedded with a ring-shaped mass member at a predetermined distance from the inner peripheral surface radially outward, and a support portion that supports the mass member on the inner peripheral side of the mass member A cylindrical engine mount, wherein a dynamic damper is formed by the rubber spring and the mass member.   2. The cylindrical engine mount according to claim 1, wherein a spring constant in a radial direction of the support portion is larger than a spring constant in a radial direction of a rubber elastic body of the rubber vibration isolating structure.   The cylindrical engine mount according to claim 1 or 2, wherein a resonance frequency of the dynamic damper is tuned in accordance with an eigenvalue of the first bracket.   The cylindrical engine mount according to claim 1, wherein an outer diameter of the mass member is smaller than an inner diameter of the outer cylinder member.