Liquid-sealed mount

Abstract

We disclose a liquid-filled mount that can more effectively suppress noise. [Solution] The liquid-sealed mount 10 comprises a main body 12 with one end closed by a main body rubber 14 and the other end closed by a diaphragm 16, a membrane 34 that separates the inside of the main body 12 into a first liquid chamber 22f and a second liquid chamber 22s, a plurality of struts 44 arranged on both sides of the membrane 34 in the axial direction and extending radially from a predetermined point, and a passage 33 that connects the first liquid chamber 22f and the second liquid chamber 22s, wherein the membrane 34 has one or more projection groups 52 consisting of a plurality of protrusions arranged on a circle substantially concentric with the predetermined point, and at least one projection group 52 satisfies y > 2x + 2a when x is the average value of the distance between adjacent protrusions 50 in the circumferential direction, a is the diameter of the protrusions 50, and y is the width of the struts 44.

Description

Technical Field

[0001] This specification discloses a hydraulic mount that supports an in-vehicle unit and attenuates the input vibration in a vehicle.

Background Art

[0002] Conventionally, in a vehicle, a hydraulic mount is widely known for supporting an in-vehicle unit. For example, Patent Document 1 discloses a hydraulic mount including a liquid chamber closed by a rubber-like elastic body and a diaphragm, an elastic partition membrane partitioning the liquid chamber into two, and an orifice communicating the two partitioned liquid chambers. In this Patent Document 1, in order to prevent the partition membrane from being excessively deformed, a plurality of crossbars are arranged on both sides of the partition membrane. And in Patent Document 1, a plurality of protrusions are provided on the surface of the partition membrane.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] [[ID=3**5]]With such a configuration, the contact area when the partition membrane contacts the crossbar can be reduced, and the abnormal noise generated due to the contact can be suppressed. However, in the technology of Patent Document 1, the arrangement conditions of the protrusions, particularly, the relationship between the arrangement interval of the protrusions and the width of the crossbar, have not been sufficiently studied. Therefore, in the technology of Patent Document 1, there are cases where the protrusions cannot stably contact the crossbar.

[0005] Therefore, this specification provides a hydraulic mount in which the protrusions stably contact the crossbar, thereby more effectively suppressing noise.

Means for Solving the Problems

[0006] The liquid-sealed mount disclosed herein comprises a body closed at one end by a rubber body and at the other end by a diaphragm, a membrane separating the inside of the body into a first liquid chamber and a second liquid chamber, a plurality of struts arranged on both sides of the membrane in the axial direction and extending radially from a predetermined point, and a passage connecting the first liquid chamber and the second liquid chamber, wherein the membrane has one or more groups of protrusions arranged on a circle substantially concentric with the predetermined point, and at least one group of protrusions satisfies y > 2x + 2a, where x is the average value of the distance between adjacent protrusions in the circumferential direction, a is the diameter of the protrusions, and y is the width of the struts. [Effects of the Invention]

[0007] With this configuration, at least two protrusions are located within the width of a single rail, allowing the protrusions to make stable contact with the rail and reduce unwanted noise. [Brief explanation of the drawing]

[0008] [Figure 1] This is a cross-sectional view of the liquid-filled mount and an exploded perspective view of the orifice unit. [Figure 2] This is a plan view of the membrane. [Figure 3] Figure 2 shows a schematic cross-sectional view along line AA and a comparative example. [Modes for carrying out the invention]

[0009] The configuration of the liquid-filled mount 10 will be described below with reference to the drawings. Figure 1 is a cross-sectional view of the liquid-filled mount 10 and an exploded perspective view of the orifice unit 30. The liquid-filled mount 10 is used in vehicles to attach on-board units (not shown), such as engines, to the vehicle body. The liquid-filled mount 10 also absorbs and dampens vibrations generated in the vehicle body or on-board units, thereby quickly stabilizing the vibrations and supporting the on-board units in a stable state.

[0010] The liquid-sealed mount 10 comprises a main body 12 and an orifice unit 30. The main body 12 further comprises a substantially cylindrical housing 18, a main body rubber 14, and a diaphragm 16. The main body rubber 14 is made of a rubber-like elastic material and is a member that closes one axial end of the housing 18. The main body rubber 14 is provided with a fastening portion 20 that is fastened to an on-board unit or vehicle body. The main body rubber 14 has elasticity to the extent that it deforms in response to vibrations of the on-board unit or vehicle body. The diaphragm 16 is a membrane-like member that closes the other axial end of the housing 18. The diaphragm 16 has flexibility to the extent that it deforms in response to pressure changes inside the main body 12. The periphery of the diaphragm 16 is liquid-tightly fixed to the inner circumferential surface of the housing 18. The inside of the main body 12 is filled with an incompressible liquid.

[0011] An orifice unit 30 is arranged inside the main body 12. The orifice unit 30 divides the inside of the main body 12 into two spaces in the axial direction and forms a passage 33 that communicates with these two spaces. Hereinafter, the space above the orifice unit 30 will be referred to as the "first liquid chamber 22f," and the space below the orifice unit 30 will be referred to as the "second liquid chamber 22s." In this example, the orifice unit 30 is composed of a first orifice member 32f, a second orifice member 32s, and a membrane 34.

[0012] The first orifice member 32f and the second orifice member 32s have almost the same structure, although they are inverted vertically. Therefore, in the following, unless there is a need to distinguish between the first orifice member 32f and the second orifice member 32s, the subscripts f and s will be omitted, and they will be referred to as "orifice member 32". The orifice member 32 has a cylindrical portion 36, a flange portion 38, and a plurality of crossbars 44. The flange portion 38 extends from the outer circumferential surface of the cylindrical portion 36 to the inner circumferential surface of the main body 12. The two orifice members 32f and 32s are stacked vertically with a membrane 34 in between and fixed in place. As a result, a passage 33 is formed between the two vertically aligned flange portions 38, enclosed by the two flange portions 38, the outer circumferential surface of the cylindrical portion 36, and the inner circumferential surface of the main body 12. Each flange portion 38 has a partition wall 40 that rises from the surface of the flange portion 38 and divides the passage 33. In addition, a notch, i.e., an inlet / outlet 42, is formed in the flange portion 38 adjacent to the partition wall 40. Liquid moving from the first liquid chamber 22f to the second liquid chamber 22s enters the passage 33 through the inlet / outlet 42 of the first orifice member 32f, and enters the second liquid chamber 22s through the inlet / outlet 42 of the second orifice member 32s. Conversely, when liquid moves from the second liquid chamber 22s to the first liquid chamber 22f, it follows the reverse path.

[0013] A membrane 34 is provided between the two cylindrical sections 36. The membrane 34 is a film that divides the cylindrical sections 36 in the axial direction. This membrane 34 has enough flexibility to deform when the pressure in the liquid chambers 22f and 22s fluctuates. Multiple protrusions 50 are provided on the surface of the membrane 34 (both the upper and lower surfaces), which will be described later.

[0014] A connecting ring 46 and a number of struts 44 are provided on both axial sides of the membrane 34. The connecting ring 46 is positioned concentrically with the cylindrical portion 36, and the number of struts 44 are stretched between the connecting ring 46 and the cylindrical portion 36. The number of struts 44 are arranged radially with the connecting ring 46 as the center. In Figure 1, eight struts 44 are arranged at equal intervals.

[0015] Next, let's briefly explain the function of the liquid-sealed mount 10. Suppose the in-vehicle unit fastened to the liquid-sealed mount 10 vibrates, and the main rubber body 14 is pulled upward significantly. In this case, the volume of the first liquid chamber 22f increases, and the pressure in the first liquid chamber 22f decreases. As a result of this pressure decrease in the first liquid chamber 22f, the liquid in the second liquid chamber 22s moves through the passage 33 into the first liquid chamber 22f. At this time, in order to eliminate the decrease in internal pressure in the second liquid chamber 22s, the diaphragm 16 deforms upward, that is, in a direction that decreases the volume of the second liquid chamber 22s.

[0016] Furthermore, suppose that the main rubber 14 is pressed significantly downward due to vibrations of the in-vehicle unit. In this case, the opposite effect occurs compared to when it moves upward. That is, the volume of the first liquid chamber 22f decreases, and the pressure in the first liquid chamber 22f increases. As a result of this increase in pressure in the first liquid chamber 22f, the liquid in the first liquid chamber 22f moves through the passage 33 to the second liquid chamber 22s. At this time, in order to relieve the increase in internal pressure of the second liquid chamber 22s, the diaphragm 16 deforms downward, that is, in a direction that increases the volume of the second liquid chamber 22s.

[0017] Thus, when large vibrations occur, for example, when the vehicle rises and falls significantly over speed bumps or rough roads, the fluid moves back and forth between the first fluid chamber 22f and the second fluid chamber 22s, rapidly dampening the vibrations and causing them to subside quickly. As a result, vibrations in the on-board unit are effectively suppressed, and the on-board unit is stably supported.

[0018] However, even when the vibrations input to the liquid-filled mount 10 are small, if liquid movement occurs, the vibrations can become unnecessarily prolonged and worsen. For example, if liquid movement occurs even when the vehicle is idling or when there are minute undulations while driving on a normal road surface, the vibrations will worsen and become prolonged.

[0019] Therefore, in order to prevent the liquid from flowing back and forth between the first liquid chamber 22f and the second liquid chamber 22s when the vibration is small, a membrane 34 is provided inside the cylinder portion 36. When the vibration is small and the deformation amount of the main body rubber 14, and thus the volume change of the first liquid chamber 22f is small, the volume change is absorbed by the deformation of the membrane 34. That is, when the main body rubber 14 is slightly pulled upward, the membrane 34 deflects convexly upward, and when the main body rubber 14 is slightly pressed downward, the membrane 34 deflects convexly downward. Thereby, small pressure changes associated with small volume changes in the first liquid chamber 22f are absorbed, the movement of the liquid is suppressed, and as a result, the deterioration of vibration is prevented.

[0020] Here, in order for the membrane 34 to regulate the deformation amount (to prevent the membrane 34 from deforming excessively), crossbars 44 are provided on both sides of the membrane 34. When the membrane 34 abuts against the crossbars 44, further deformation of the membrane 34 is prevented, and an excessive load is prevented from being applied to the membrane 34.

[0021] By the way, when the membrane 34 abuts against the crossbars 44, of course, some abnormal noise is generated. If this abnormal noise is large, the comfort of the passengers will decrease. Therefore, in this example, a plurality of protrusions 50 are provided on the surface of the membrane 34. The protrusions 50 are hemispherical. In this case, only the apexes of the protrusions 50 of the membrane 34 will abut against the crossbars 44. In other words, by providing the protrusions 50, the contact area between the membrane 34 and the crossbars 44 is reduced. And thereby, the abnormal noise when the membrane 34 abuts against the crossbars 44 can be reduced.

[0022] However, if the arrangement interval and size of the protrusions 50 are inappropriate, the protrusions 50 may not stably abut against the crossbars 44, and there is a possibility that the abnormal noise cannot be sufficiently reduced. Therefore, in this example, the arrangement interval and size of the protrusions 50 are set so that the protrusions 50 can stably abut against the crossbars 44. The following will explain this.

[0023] Figure 2 is a plan view of the membrane 34. The two-dot chain line in Figure 2 shows the shapes of the connecting ring 46 and the crossbar 44. Further, Figure 3 is a schematic cross-sectional view taken along the line A-A of Figure 2.

[0024] As shown in Figure 2, in addition to a plurality of randomly arranged protrusions 50, the membrane 34 further has one or more protrusion groups 52. In Figure 2, the randomly arranged protrusions 50 are shown as white small circles, and the protrusions 50 belonging to the protrusion group 52 are shown as black small circles. Each protrusion group 52 has a plurality of protrusions 50 arranged on a circle substantially concentric with the center of the cylindrical portion 36 (that is, the center of the radial shape drawn by the crossbar 44). In the example of Figure 2, the membrane 34 has two protrusion groups 52.

[0025] In the protrusion group 52, when the interval x between two adjacent protrusions 50, the diameter of the protrusion 50 is a, and the circumferential width of the crossbar 44 is y, the protrusions 50 are arranged so as to satisfy the condition of y≧2x + 2a. In such an arrangement, as shown in the upper part of Figure 3, within the width of one crossbar 44, there will always be two or more protrusions 50 located. And thereby, the posture of the membrane 34 is stabilized, and the surface of the membrane 34 itself is prevented from contacting the crossbar 44.

[0026] That is, when the interval x between the protrusions 50 is large and only one protrusion 50 exists in the crossbar 44 within the width of the crossbar 44, as shown in the middle part of Figure 3, the membrane 34 may tilt with the one protrusion 50 as a fulcrum, and the surface of the membrane 34 may contact the crossbar 44. In this case, naturally, since the contact area increases, the abnormal noise increases. On the other hand, if the arrangement satisfies the condition of y≧2x + 2a as in this example, such tilting of the membrane 34 can be suppressed, and an increase in abnormal noise can be prevented.

[0027] Furthermore, in this example, the diameter a of the protrusion 50 is made smaller than the arrangement interval x of the protrusions 50. This configuration is for the following reasons. As shown in the lower part of FIG. 3, when the diameter a of the protrusion 50 is large, the radius of curvature at the apex of the protrusion 50 becomes large accordingly, and the contact area between the protrusion 50 and the crossbar 44 tends to be large. Also, when trying to satisfy y≧2x + 2a while increasing the diameter a, it is necessary to reduce the gap x between the protrusions 50. When the diameter a of the protrusion 50 is large and the gap x is small, the average value of the thickness over the entire membrane 34 becomes large, and the flexibility of the membrane 34 deteriorates. On the other hand, as in this example and as shown in the upper part of FIG. 3, when a < x, the contact area between the protrusion 50 and the crossbar 44 can be kept small, and the flexibility of the membrane 34 can be maintained high.

[0028] By the way, such a protrusion group 52 may be one or more on one side of the membrane 34. On one side of the membrane 34, all of the plurality of protrusion groups 52 (that is, groups of the plurality of protrusions 50 arranged on a circle) may satisfy the conditions of y≧2x + 2a and x > a. Also, as another form, only some of the plurality of protrusion groups 52 may satisfy the conditions of y≧2x + 2a and x > a. In this case, at least it is desirable that the protrusion group 52 located on the innermost peripheral side satisfies the conditions of y≧2x + 2a and x > a. This is because the protrusion group 52 on the inner peripheral side is likely to collide with the crossbar 44. That is, as shown by the two-dot chain line in the upper part of FIG. 1, when the membrane 34 bends, the vicinity of the center of the membrane 34 bends the most and is likely to contact the crossbar 44. Therefore, it is desirable to arrange the protrusions 50 so as to satisfy y≧2x + 2a and x > a at the location where it is likely to contact this crossbar 44. With such a configuration, the protrusion 50 and the crossbar 44 can be stably contacted while reducing abnormal noise.

[0029] In another configuration, the protrusions 50 may be arranged such that y≧2x+2a and x>a in at least the outermost protrusion group 52 of the multiple protrusion groups 52. Furthermore, in yet another configuration, the protrusions 50 may be arranged such that y≧2x+2a and x>a in at least both the innermost protrusion group 52 and the outermost protrusion group 52 of the multiple protrusion groups 52. With this configuration, the protrusions 50 contact the struts 44 at two points in the radial direction, thereby reducing the possibility of the surface of the membrane 34 itself contacting the struts 44. This allows for a more effective reduction of abnormal noise.

[0030] Furthermore, the above description includes not only the protrusions 50 belonging to the protrusion group 52, but also randomly placed protrusions 50. However, if the membrane 34 has at least one protrusion group 52, the randomly placed protrusions 50 are not necessary.

[0031] Furthermore, the above descriptions are all examples, and other configurations may be modified as appropriate, as long as the configuration of claim 1 is achieved. For example, in the above description, the first orifice member 32f and the second orifice member 32s are configured as separate members. However, the first orifice member 32f and the second orifice member 32s may not be separated but configured as a single part. In that case, the single part may be formed, for example, by a 3D printer. Also, in the above description, the width of the strut 44 is kept constant regardless of the radial position. However, the width of the strut 44 may change depending on the radial position. For example, the width of the strut 44 may gradually increase as it approaches the radial outer side. In this case, the spacing of the projections 50 is changed according to the radial position of the projection group 52. In other words, if y(r) is the width of the strut 44 at radius r, a(r) is the diameter of the projection 50 belonging to the projection group 52 located at radius r, and x(r) is the spacing between them, then the projections 50 should be arranged such that y(r)≧2x(r)+2a(r) and x(r)>a(r). [Explanation of Symbols]

[0032] 10 Liquid-filled mount, 12 Main body, 14 Main body rubber, 16 Diaphragm, 18 Housing, 20 Fastening part, 22f First liquid chamber, 22s Second liquid chamber, 30 Orifice unit, 32 Orifice member, 33 Passage, 34 Membrane, 36 Cylindrical part, 38 Flange part, 40 Partition wall, 42 Inlet / outlet, 44 Rivet, 46 Connecting ring, 50 Projection, 52 Projection group.

Claims

[Claim 1] The main body has one end sealed with rubber and the other end sealed with a diaphragm, A membrane separates the inside of the main body into a first liquid chamber and a second liquid chamber, Multiple struts are arranged on both sides of the membrane in the axial direction, extending radially from a predetermined point, A passage 33 connecting the first liquid chamber and the second liquid chamber, The membrane comprises one or more groups of protrusions, each consisting of multiple protrusions arranged on a circle substantially concentric with the predetermined point. At least one group of protrusions satisfies y > 2x + 2a, where x is the average distance between adjacent protrusions in the circumferential direction, a is the diameter of the protrusion, and y is the width of the rib. A liquid-sealed mount characterized by the following features.

Images