Patent Application
20240060541
The present invention relates to a disc brake shim and a disc brake.
In general, disc brakes are widely used in automobiles and the like (refer to Patent Literature 1 (Japanese Patent Laid-Open No. 2010-31960), for example).
If the brake pad 30 is directly pressed to the disc rotor 60 by the pressing member 70 during braking as described above, a back metal 40 of the brake pad and the pressing member 70 relatively move, and each part of the brake vibrates due to frictional vibration or the like that is generated between the brake pad 30 and the disc rotor 60, so that abnormal noise commonly referred to as squeal may occur.
In order to prevent occurrence of such squeal, a shim S is interposed between a pad material P formed of the brake pad 30 and the back metal 40, and the pressing member 70, as illustrated in
However, according to the study by the present inventors, even the shim formed of the above described rubber-coated metal (RCM) cannot always sufficiently satisfy the needs of automobile users for comfort and quietness during driving, which have been increasing more and more in recent years, and therefore, there has been a demand for disc brake shims that can even more suppress vibrations causing squeal.
In order to solve the above described technical problem, the present inventors have reached the idea of adopting a rubber layer having a plurality of pores provided therein, as a rubber layer that is provided on the metal sheet that forms a disc brake shim.
However, as a result of investigations by the present inventors, it has been found that in the above described disc brake shim, when a chemically decomposable (thermally decomposable) foaming agent is used to form pores in the rubber layer, the decomposed gas does not remain in the rubber and escapes to the outside in many cases, and it is very difficult to control the expansion rate (pore ratio) of the resulting rubber layer.
Difficulty in controlling the above described expansion rate leads to a large variation in the thickness of the rubber layer and a variation in the vibration control performance, and there has been a demand for disc brake shims that are easy to manufacture and have excellent quality stability.
Accordingly, an object of the present invention is to provide a novel disc brake shim and disc brake that can effectively suppress occurrence of vibration and squeal, are easy to manufacture and have excellent quality stability.
As a result of earnest study conducted by the present inventors to attain the above described object, the present inventors have found that the above described technical problem can be solved by a disc brake shim having a base material layer formed of a metal sheet, and a rubber layer that is laminated and disposed on at least a part of a main surface on one side of the base material layer, and contains pores derived from a plurality of hollow microcapsules inside, and have completed the present invention based on the present findings.
In other words, the present invention provides
According to the present invention, it is considered that not only the rubber layer provided on the base material layer hardly transmits vibration of the brake pads and the like because the rubber layer has a low density with pores derived from a plurality of hollow microcapsules inside, but also the rubber layer deforms to follow the vibration of the brake pads and the like to easily convert the vibration into thermal energy because the rubber layer has flexibility, and further the rubber layer can easily convert vibration of an external member into frictional heat because the rubber layer has a high friction coefficient.
Further, in the rubber layer provided on the above described base material, a plurality of pores is easily formed inside while the pore ratio and thickness are easily controlled by using the plurality of hollow microcapsules.
Consequently, according to the present invention, it is possible to provide a novel disc brake shim and disc brake that can effectively suppress occurrence of vibration and squeal, are easy to manufacture and have excellent quality stability.
A disc brake shim according to the present invention has a base material layer formed of a metal sheet, and a rubber layer that is laminated and disposed on at least a part of a main surface on one side of the base material layer and contains pores derived from a plurality of hollow microcapsules inside.
As the disc brake shim according to the present invention, one or more selected from a first disc brake shim according to the present invention and a second disc brake shim according to the present invention can be cited.
The first disc brake shim according to the present invention has a base material layer formed of a metal sheet, and the rubber layer that is laminated and disposed on at least a part of a main surface on one side of the base material layer, the rubber layer being an outermost layer once arranged.
Further, the second disc brake shim according to the present invention is formed of a laminated structure with three or more layers having at least a base material layer formed of a metal sheet, and the rubber layer that is laminated and disposed on a main surface on one side of the base material layer, the rubber layer being disposed as an intermediate layer of the above described laminated structure.
Hereinafter, the disc brake shim according to the present invention will be described while the first disc brake shim according to the present invention and the second disc brake shim according to the present invention that are exemplary modes of the disc brake shim of the present invention are properly mentioned.
In the present application documents, the disc brake shim means the one in a state in which respective adjacent layers forming the disc brake shim are chemically or physically fixed.
In the disc brake shim according to the present invention, the metal sheet forming the base material layer is not particularly limited, but it is possible to cite sheet materials formed of a stainless steel (ferritic, martensitic, austenitic, and the like), iron, a plating material, aluminum and the like, and a metal sheet formed of a sheet material formed of a stainless steel or iron is preferable.
In the disc brake shim according to the present invention, the metal sheet forming the base material layer may be formed by joining a plurality of metal sheets by pasting or the like, and as the metal sheet, a joined sheet of a stainless steel sheet and an iron sheet is preferable.
In the disc brake shim according to the present invention, a thickness of the metal sheet forming the base material layer is not particularly limited, but is normally 0.4 to 0.8 mm.
In the disc brake shim according to the present invention, the rubber layer contains pores derived from a plurality of hollow microcapsules inside.
A thickness of the rubber layer is preferably 30 to 200 μm, more preferably 50 to 200 μm, even more preferably 60 to 140 μm, and even more preferably 80 to 120 μm.
The thickness of the above described rubber layer means an arithmetic mean value at a time of thicknesses at 10 spots being measured by using a linear gauge (DG-925 made by Ono Sokki Co., Ltd.).
In the disc brake shim according to the present invention, the thickness of the rubber layer is within the above described range, and thereby it is possible to easily provide a disc brake shim having a desired density, and having a desired flexibility and friction coefficient.
The above described rubber layer is preferably a heat-treated product of a rubber composition coating layer (coating film of a rubber composition), and is porous because hollow portions of many hollow microcapsules blended in rubber become pores in the rubber.
A porosity of the above described rubber layer is preferably 10% to 85%, more preferably 15% to 80%, and even more preferably 25% to 75%.
In the present application documents, the above described porosity means a value calculated by an expression below.
Porosity (%)=(1−(Thickness of rubber layer when compressed/Thickness of rubber layer))×100
(Note that the thickness of the rubber layer means an arithmetic mean value at the time of the thicknesses at 10 spots being measured by using the aforementioned linear gauge, and the thickness of the rubber layer when compressed means an arithmetic mean value when the thicknesses at 10 spots are measured by using the aforementioned linear gauge, with respect to the rubber layer when compressed with a pressing force of 34.3 MPa.)
In the disc brake shim according to the present invention, the porosity of the rubber composition coating layer is within the above described range, and thereby it is possible to easily form the rubber layer having a desired density, flexibility and friction coefficient.
A rubber composition that forms the rubber composition coating layer preferably contains a polymer (rubber component) with a Moony value of 10 to 70, and more preferably contains a polymer with a Moony value of 20 to 60.
In the present application documents, the Mooney value means a value that is measured by a method specified in JIS K6300-1 by using Mooney Viscometer SMV-201 made by Shimadzu Corporation.
When the Mooney value of the polymer is less than 10, deformation of the polymer easily becomes excessive, and when the Mooney value is more than 70 on the contrary, deformation of the polymer easily becomes insufficient.
As the polymer, it is possible to cite one or more selected from nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), fluororubber, ethylene propylene diene rubber (EPDM), acrylic rubber and the like, and one or more selected from nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), and fluororubber is preferable.
Furthermore, as the above described nitrile rubber (NBR), in order to give oil resistance, a nitrile rubber with an AN value (content of acrylonitrile group in NBR) of 39 to 52 is preferable, and a nitrile rubber with an AN value of 40 to 48 is more preferable.
The rubber composition coating layer contains the above described polymer, and thereby it is possible to easily obtain the rubber layer having desired properties.
The rubber composition coating layer preferably contains 40 to 70% by mass of the above described polymer, more preferably 45 to 65% by mass of the above described polymer, and even more preferably 50 to 60% by mass of the above described polymer, when converted to a solid content.
The rubber composition coating layer contains the above described polymer in the above described ratio, and thereby it is possible to effectively suppress loss of elasticity of the rubber layer due to compression during braking.
In the disc brake shim according to the preset invention, the rubber layer contains pores derived from a plurality of hollow microcapsules inside.
In the present application, the hollow microcapsules each means a microscopic container with a diameter of about 1 to 100 μm having a core shell structure, which is a granular container with a cavity-like (hollow) core portion covered with a shell portion formed of a wall material.
As the above described hollow microcapsules, it is possible to cite, for example, glass hollow microbeads, ceramic hollow microbeads, resin hollow microbeads and the like, and heat-treated microbeads in each of which a core portion where a heat-decomposable foaming agent is encapsulated is covered with a shell portion formed of a thermally expandable material (the shell portion that is thermally expanded while maintaining a granular shape with evaporation of the foaming agent).
As the above described heat-decomposable foaming agent, a heat-decomposable foaming agent with a foaming temperature of 120° C. or higher is preferable, and a heat-decomposable foaming agent with a foaming temperature of 150 to 210° C. is more preferable.
As a heat-decomposable foaming agent, it is possible to cite one or more selected from, for example, an azodicarbonamide foaming agent, dinitrosopentamethylene tetramine foaming agent, oxybisbenzenesulfonylhydrazide foaming agent, sodium bicarbonate foaming agent and the like, and aliphatic hydrocarbon.
The rubber composition coating layer preferably contains 5 to 50% by mass of the above described hollow microcapsules, and more preferably contains 10 to 30% by mass of the above described hollow microcapsules, when converted to a solid content.
The rubber composition coating layer contains the above described hollow microcapsules in the above described ratio, and thereby it is possible to easily control the pore ratio in the resulting rubber layer within a desired range, and easily form the rubber layer having a desired density, and having a desired flexibility and friction coefficient.
Furthermore, the rubber composition coating layer may contain a vulcanizing agent and a vulcanization accelerator. The vulcanizing agent is preferably contained in a large amount so as to increase a vulcanization density, and in the case of sulfur vulcanization, a sulfur compound amount is preferably 1.5 to 4.5 g (1.5 to 4.5 phr (parts per hundred rubber)) for 100 gram of polymer that is a rubber component.
Furthermore, as the vulcanization accelerator, it is preferable to use a high-speed vulcanization accelerator that rises with a time to T50 within 4 minutes according to curast data (150° C.). Note that the time to T50 according to the curast data (150°) means a time required until a vulcanization degree of rubber reaches T50 (elapsed time until reaching 50% of maximum torque) when vulcanization is performed at 150° C. by using a curast testing machine (JSR curast meter III made by Nichigo Shoji Co., Ltd.).
Further, the rubber layer preferably has a closed cell rate of 30% or more, and more preferably has a closed cell rate of 50% or more, though the rubber layer is not particularly limited.
In the present application documents, the closed cell rate of the rubber layer means a value obtained by obtaining a volume of a closed cell part by using an air comparison pycnometer (930 type made by Toshiba Beckman Co., Ltd.) and calculating the closed cell rate by an expression below.
Closed cell rate (%)=Closed cell part volume (cm3)/Apparent volume (cm3)×100
Further, “apparent volume” in the above described expression means a value obtained from a product of the thickness of the rubber layer obtained from the arithmetic mean value of the thicknesses at 10 spots by using the aforementioned linear gauge, and a surface area of the rubber layer.
Note that the above described air comparison pycnometer is for obtaining a volume of closed cells from a volume change when an object to be measured is disposed in water and a water pressure is raised, and is for causing water to enter in cells by raising water pressure to cause a volume change to measure the volume amount of the closed cell part from the change amount because water hardly enters into the cells in the case of closed cells, while the cells formed in the object to be measured are continuous cells, water easily enters in the cells, and volume change does not occur even when the water pressure is raised.
In the disc brake shim according to the present invention, the porosity of the rubber layer is within the above described range, and therefore, it is possible to obtain the rubber layer that has a desired density, and has a desired flexibility and friction coefficient.
Further, the closed cell rate of the rubber layer is within the above described range, and thereby control of the above described porosity in manufacturing becomes easy, and it is possible to provide the disc brake shim in which the above described density, flexibility and friction coefficient are easily controlled.
When a chemically decomposable (thermally decomposable) foaming agent is simply dispersed in the rubber layer to form pores, a part of decomposed gas escapes from the rubber layer, or pores tend to be formed into continuous cell shape, so that it becomes very difficult to control the porosity (pore ratio) and the closed cell rate of the resulting rubber layer, the thickness of the rubber layer tends to vary, and vibration control performance tends to vary.
In contrast to this, in the disc brake shim according to the present invention, the pores in the rubber layer are formed of hollow microcapsules, so that in addition to that cells hardly escape from the rubber layer, closed pores are easily formed, and for this reason, it is possible to easily provide the rubber layer in which the pore ratio and the thickness of the rubber layer are easily controlled.
In the disc brake shim according to the present invention, it is possible to form the rubber layer, for example, by dissolving a rubber composition containing respective desired amounts of polymer and hollow microcapsules in an organic solvent to prepare a coating liquid, applying the coating liquid to a metal sheet to be a base material layer, and fixing the coating liquid.
The above described organic solvent is not limited as long as it can dissolve the above described rubber composition, but it is preferable to use an organic solvent prepared by mixing an ester solvent in a ratio of 10 to 90% by mass with respect to 10 to 90% by mass of aromatic hydrocarbon solvent (ketone type is also possible) such as toluene. Furthermore, as the coating liquid, a coating liquid that is prepared by dissolving the above described rubber composition in the above described organic solvent so that the solid content concentration is 10 to 60% by mass is preferable.
A coating method of the coating liquid containing the rubber composition is not particularly limited, but the coating liquid is preferably applied by a skimmer coater, a roll coater or the like that can control a coating thickness.
After the coating liquid is applied, heat treatment is preferably performed at 60 to 150° C. for 3 to 15 minutes to dry the solvent, thereafter, heat treatment is preferably performed at 150 to 220° C. for 3 to 15 minutes to crosslink the rubber component, and the rubber layer is fixed while being formed.
At this time, it is preferable to select a type of microcapsules to be used and adjust a compound ratio so that the porosity and the closed cell rate of the resulting rubber layer have desired values.
Inside the rubber layer obtained by the above described treatment, many pores corresponding to cavity portions (hollow portions) of the hollow microcapsules are formed.
In the disc brake shim according to the present invention, a plurality of pores derived from the hollow microcapsules are provided inside the rubber layer, so that it is possible to easily control the porosity and the closed cell rate in the rubber layer, and further the thickness of the rubber layer as compared with the case in which pores are provided inside the rubber layer by using a chemically decomposable (thermally decomposable) foaming agent, and for this reason, in the present invention, it is possible to provide the disc brake shim that is easy to manufacture and has excellent quality stability.
As a specific mode of the disc brake shim according to the present invention, it is possible to cite the first disc brake shim according to the present invention as described above, and here, the first disc brake shim according to the present invention has a base material layer formed of a metal sheet, and the above described rubber layer that is laminated and disposed on at least a part of a main surface on one side of the base material layer to be an outermost layer at a time of arrangement.
In the first disc brake shim according to the present invention, the above described rubber layer is preferably oriented to face a pad material or a pressing member, at the time of arrangement.
Hereinafter, an exemplary mode of the first disc brake shim according to the present invention will be described by using
In the present exemplary mode, in a braking time, the disc brake shim S is pressed (in a lower direction from an upper side in
Consequently, according to the first disc brake shim according to the present invention shown in
In the present exemplary mode, in the braking time, the disc brake shim S is pressed (in a lower direction from an upper side in
Consequently, in the disc brake shim according to the present invention shown in
In the first disc brake shim according to the present invention, the rubber layer can be laminated and disposed on a part of the main surface on at least one side of the base material layer formed of the metal sheet, and is preferably laminated and disposed on the entire main surface on one side of the base material layer formed of the metal sheet (as illustrated in
In the first disc brake shim according to the present invention, rubber layers may be laminated and disposed on main surfaces on both sides of the base material layer formed of the metal sheet, and may be respectively laminated and disposed on the entire main surfaces on both sides of the base material layer formed of the metal sheet.
The first disc brake shim according to the present invention according to the exemplary mode shown in
The first disc brake shim according to the present invention may have a solid rubber layer, in addition to the base material layer formed of a metal sheet, and the rubber layer that is laminated and disposed on at least a part of the main surface on one side of the base material layer to be the outermost layer at the time of arrangement.
In the present application documents, the solid rubber layer means a rubber layer that does not have pores derived from hollow microcapsules or a foaming agent.
A thickness of the solid rubber layer is preferably 25 to 250 μm, more preferably 50 to 200 μm, and even more preferably 100 to 180 μm.
The thickness of the above described solid rubber layer means an arithmetic mean value at a time of measuring thicknesses at 10 spots by using the above described linear gauge.
As a polymer (rubber component) forming the solid rubber layer, one or more selected from nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), fluororubber, ethylene propylene diene rubber (EPDM) and acrylic rubber, and the like, and one or more selected from nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), and fluororubber is preferable.
Furthermore, as the above described nitrile rubber (NBR), in order to give oil resistance, a nitrile rubber with an AN value (content of acrylonitrile group in NBR) of 25 to 50 is preferable, and a nitrile rubber with an AN value of 30 to 45 is more preferable.
Furthermore, the solid rubber layer may contain a vulcanizing agent and a vulcanization accelerator. The vulcanizing agent is preferably contained in a large amount so as to increase a vulcanization density, and in the case of sulfur vulcanization, a sulfur compound amount is preferably 1.5 to 4.5 g (1.5 to 4.5 phr (parts per hundred rubber)) for 100 gram of polymer that is a rubber component.
Furthermore, as the vulcanization accelerator, it is preferable to use a vulcanization accelerator at a high rate with a time to T50 rising within 4 minutes according to curast data (150° C.).
In the disc brake shim according to the present invention, it is possible to form the solid rubber layer by, for example, dissolving a rubber composition containing a desired amount of polymer in an organic solvent to prepare a coating liquid, applying the coating liquid to an object to be coated such as the base material layer, and fixing the coating liquid.
The organic solvent is not limited as long as it can dissolve the above described rubber composition, but it is preferable to use an organic solvent prepared by mixing an ester solvent in a ratio of 10 to 90% by mass with respect to 10 to 90% by mass of aromatic hydrocarbon solvent (ketone type is also possible) such as toluene. Furthermore, as the coating liquid, a coating liquid that is prepared by dissolving the above described rubber composition in the above described organic solvent so that the solid content concentration is 10 to 60% by mass is preferable.
A coating method of the coating liquid containing the rubber composition is not particularly limited, but the coating liquid is preferably coated by a skimmer coater, a roll coater or the like that can control a coating thickness.
The first disc brake shim according to the present invention according to the exemplary mode shown in
The first disc brake shim according to the present invention according to the exemplary mode shown in
The first disc brake shim according to the present invention may have an adhesive layer, in addition to the base material layer formed of a metal sheet, and the rubber layer that is laminated and disposed on at least a part of the main surface on one side of the base material layer to be the outermost layer at the time of arrangement.
As an adhesive forming the adhesive layer, it is possible to cite one or more selected from an acrylic adhesive, silicon adhesive, rubber adhesive, urethane adhesive and the like, and one or more selected from an acrylic adhesive and silicon adhesive is more preferable.
When the adhesive is an acrylic adhesive, one or more selected from a metal chelate crosslinking agent, isocyanate crosslinking agent, epoxy crosslinking agent and the like are preferably further used as a crosslinking agent.
The first disc brake shim according to the present invention has an adhesive layer, and thereby can produce an excellent ability to prevent squeal by an excellent vibration control effect of the adhesive.
The disc brake shims S according to the exemplary modes shown in
The disc brake shims S shown in
The first disc brake shim according to the present invention may have a plurality of base material layers each formed of a metal sheet.
The first disc brake shim according to the present invention more easily improves vibration control performance as a constraint vibration control structure, by having the plurality of base material layers each formed of a metal sheet.
In this case, as the metal sheet forming the plurality of base material layers respectively, same metal sheet as the aforementioned metal sheet can be cited.
The disc brake shim S according to the exemplary mode shown in
The disc brake shim S according to the exemplary mode shown in
The disc brake shim S according to the exemplary mode shown in
The disc brake shim S according to the exemplary mode shown in
The disc brake shim S according to the exemplary mode shown in
In each of the disc bake shims S according to exemplary modes shown in
The first disc brake shim according to the present invention may be a base shim or a cover shim, in a laminated shim in which the cover shim is laminated and disposed on the base shim.
For example, the first disc brake shim according to the present invention may be a base shim BS or a cover shim CS in a laminated shim MS in which the cover shim CS is laminated on the base shim BS, in a vertical sectional view of an exemplary mode of use of a disc brake shim according to the present invention illustrated in
In this case, only either one of the base shim and the cover shim forming the laminated shim may be the first disc brake shim according to the present invention, or both of the base shim and the cover shim that form the laminated shim may be the first disc brake shim according to the present invention.
Note that in the present application documents, the base shim that forms the laminated shim means a shim that is disposed on a pad material side at the time of arrangement, and the cover shim that forms the laminated shim means a shim that is oriented on a pressing member side at the time of arrangement. Furthermore, in the present application documents, the cover shim and the base shim means the cover shim and the base shim that are in a state in which entire joined surfaces of both of them are not chemically or physically fixed, but in a state in which they are adjacently disposed.
When the base shim (the base shim BS illustrated in
Furthermore, when the cover shim (the cover shim CS illustrated in
When only the base shim that forms the laminated shim is the first disc brake shim according to the present invention, the structure of the cover shim can be properly selected from the conventionally known cover shims and is not particularly limited.
For example, as illustrated in
Furthermore, as illustrated in each of
Furthermore, as illustrated in
As the base material layers formed of the metal sheets and the solid rubber layers of the above described cover shims, it is possible to cite the base material layer and the solid rubber layer that are the same as described above respectively.
As a specific mode of the disc brake shim according to the preset invention, it is possible to cite the second disc brake shim according to the present invention as described above other than the first disc brake shim according to the present invention, and here, the second disc brake shim according to the present invention is formed of a laminated structure with three or more layers having at least a base material layer formed of a metal sheet, and the rubber layer that is laminated and disposed on a main surface on one side of the base material layer, the rubber layer being disposed as an intermediate layer of the above described laminated structure.
The second disc brake shim according to the present invention is formed of a laminated structure with three or more layers, and the rubber layer is disposed as the intermediate layer. Here, the intermediate layer means a layer that is located on either one of the inner sides except for an outermost layer, of the plurality of constituent layers that are three or more layers.
Hereinafter, an exemplary mode of the second disc brake shim according to the present invention will be described by using
The second disc brake shim according to the present invention may have an adhesive layer in addition to the base material layer formed of a metal sheet, and the rubber layer that is laminated and disposed on the main surface on one side of the base material layer.
As the adhesive that forms the adhesive layer, the same adhesives as described above can be cited.
Hereinafter, an exemplary mode of the second disc brake shim according to the present invention will be described.
In the present exemplary mode, the disc brake shim S is pressed by the pressing member such as a piston provided in a caliper (in a downward direction from an upper side in
Consequently, according to the second disc brake shim according to the present invention shown in FIG. 35, it is possible to effectively suppress occurrence of vibration and squeal.
The disc brake shim according to the present invention may have a solid rubber layer in addition to the base material layer formed of a metal sheet, and the rubber layer that is laminated and disposed on the main surface on one side of the base material layer.
In the present application documents, details of the solid rubber layer and a method for forming the solid rubber layer are the same as described above.
As shown in
In the present exemplary mode, the disc brake shim S is also pressed by a pressing member such as a piston provided in the caliper (in a downward direction from an upper side in
The disc brake shim S according to the exemplary mode shown in
The second disc brake shim according to the present invention may have a plurality of base material layers formed of a metal sheet.
The second disc brake shim according to the present invention has a plurality of base material layers formed of a metal sheet, and thereby more easily improves vibration control performance as a constraint vibration control structure.
In this case, as the metal sheet that forms each of the plurality of base material layers, a same metal sheet as described above can be cited.
As shown in
In the present exemplary mode, the disc brake shim S is also pressed by a pressing member such as a piston provided in a caliper (in the downward direction from an upper side in
The disc brake shim S according to the exemplary mode shown in
The disc brake shim S shown in
In the present exemplary mode, the disc brake shim S is also pressed (in the downward direction from an upper side in
The disc brake shim S according to the exemplary mode shown in
The disc brake shim S shown in
In the present exemplary mode, the disc brake shim S is also pressed (in the downward direction from an upper side in
The disc brake shim S according to the exemplary mode shown in
The disc brake shim S shown in
In the present exemplary mode, the disc brake shim S is also pressed (in the downward direction from an upper side in
The disc brake shim S according to the exemplary mode shown in
The second disc brake shim according to the present invention may be a base shim or cover shim, in a laminated shim in which the cover shim is laminated and disposed on the base shim.
For example, the second disc brake shim may be a base shim BS or a cover shim CS in a laminated shim MS in which the cover shim CS is laminated and disposed on the base shim BS, in a vertical sectional view showing an outline of an exemplary mode of use of the second disc brake shim according to the present invention illustrated in
In this case, only either one of the base shim and the cover shim that form the laminated shim may be the second disc brake shim according to the present invention, or both the base shim and the cover shim that form the laminated shim may be the second disk brake shims according to the present invention.
Note that as described above, in the present application documents, the base shim that forms the laminated shim means a shim disposed on a pad material side at a time of arrangement, and the cover shim that forms the laminated shim means a shim disposed on a pressing member side at the time of arrangement. Further, in the preset application documents, the cover shim and the base shim mean the cover shim and the base shim that are not in a state in which entire joint surfaces of both of the shims are not chemically or physically fixed, but in a state of being disposed adjacently to each other.
When only the base shim forming the laminated shim is the disc brake shim according to the present invention, the structure of the cover shim can be properly selected from the conventionally known cover shims, and is not particularly limited.
For example, as illustrated in
Further, as illustrated in each of
Furthermore, as illustrated in
As the base material layers formed of the metal sheets and the solid rubber layers of the above described cover shims, it is possible to cite the base material layer and the solid rubber layer that are same as described above respectively.
According to the present invention, it is considered that not only the rubber layer provided on the base material layer hardly transmits vibration of a brake pad and the like because the rubber layer has a low density with a plurality of pores, but also the rubber layer deforms to follow vibration of the brake pad and the like to easily convert the vibration into thermal energy because the rubber layer has flexibility, and the rubber layer can easily convert vibration of the outer member into a frictional heat because the rubber layer has a high friction coefficient.
Further, according to the present invention, a plurality of pores derived from hollow microcapsules are provided inside the rubber layer, and thereby it is possible to easily control the pore ratio in the rubber layer and the thickness of the rubber layer as compared with the case in which pores are provided inside the rubber layer by using a chemically decomposable (thermally decomposable) foaming agent.
Consequently, according to the present invention, it is possible to provide a novel disc brake shim that can effectively suppress occurrence of vibration and squeal, is easy to manufacture, and has excellent quality stability.
Next, a disc brake according to the present invention will be described.
The disc brake according to the present invention is a disc brake having pad materials disposed on both sides in an axial direction of a disc rotor, and shims that are adjacently disposed on opposite sides from the disc rotor, of the pad materials,
wherein each of the shims is the disc brake shim according to the present invention.
As the disc brake according to the present invention, a disc rotor having a mode as shown in
A disc brake B illustrated in
The disc brake B illustrated in
In the disc brake according to the present invention, details of the disc brake shim are as described above.
When the shim forming the disc brake according to the present invention is formed by laminating and disposing a cover shim on a base shim, and the above described cover shim is the first disc brake shim according to the present invention, the rubber layer forming the cover shim is preferably oriented to face a pressing member side (the pressing member 70 illustrated in
When the shim forming the disc brake according to the present invention is formed by laminating and disposing a cover shim on a base shim, and the above described base shim is the first disc brake shim according to the present invention, the rubber layer forming the base shim is preferably oriented to face a pad material side (a brake pad 30 side illustrated in
Furthermore, in the disc brake according to the present invention, as specific examples of the other component members such as the disc rotor, and the brake pads, conventionally known component members can be cited, and the other component members are not particularly limited.
According to the present invention, it is considered that not only the rubber layer forming the disc brake shim hardly transmits vibration of a brake pad and the like because the rubber layer has a low density with a plurality of pores, but also the rubber layer deforms to follow vibration of the brake pad and the like to easily convert the vibration into thermal energy because the rubber layer has flexibility, and furthermore, the rubber layer can easily convert vibration of the outer member into a frictional heat because the rubber layer has a high friction coefficient.
Consequently, according to the present invention, it is possible to provide a novel disc brake that can effectively suppress occurrence of vibration and squeal.
Next, the present invention will be more specifically described by citing examples, but these examples are only illustrations, and do not intend to restrict the present invention.
A rubber compound formed from components shown in Table 1, and compounded to have 60% by mass of a polymer, 12% by mass of hollow microcapsules, a total of 3% by mass of a vulcanizing agent and a vulcanization accelerator, and 25% by mass of a filler was dissolved in a mixed liquid of toluene and ethyl acetate (toluene:ethyl acetate=70:30 in a volume ratio) so as to have 40% by mass of a solid content concentration to prepare a coating liquid.
Subsequently, the above described coating liquid was applied onto the entire main surface on one side of the base material formed of a stainless steel sheet (SUS sheet) with a thickness of 0.5 mm to have a thickness of 250 μm by using a roll coater to form a rubber compound coating layer, and thereafter heating treatment was applied thereto at 120° C. for 10 minutes to evaporate toluene and ethyl acetate and dry it, whereby the rubber layer was fixed and formed. Thereafter, heating treatment was performed at 200° C. for 10 minutes, and thereby the disc brake shim material (width 240 mm, length 15 mm, thickness 0.6 mm, porosity of the rubber layer 41%, closed cell rate of the rubber layer 37%) having the rubber layer with a thickness of 100 μm on the main surface on one side of the base material formed of an SUS sheet was obtained.
The obtained disc brake shim material was provided for measurement of vibration dampening property evaluation as follows, as a test piece of the disc brake shim that is oriented to face the pad material at the time of arrangement.
In the state in which the obtained disc brake shim material was disposed so that the rubber layer abuts on a support stand of a stainless steel sheet with a thickness of 5 mm of a loss coefficient measuring device (MS18143 made by Bruel & Kjar Sound & Vibration Measurement A/S), a loss coefficient η was measured under the conditions described below in conformity with the central exciting method (constrained steel sheet method) specified in JIS G0602.
Results are shown in Table 2.
Note that the higher the loss coefficient TI, the higher the vibration dampening properties.
A rubber compound formed from the components shown in Table 1, and compounded to contain 60% by mass of a polymer, 12% by mass of hollow microcapsules, a total of 3% by mass of a vulcanizing agent and a vulcanization accelerator, and 25% by mass of a filler was dissolved in a mixed liquid of toluene and ethyl acetate (toluene:ethyl acetate=70:30 in a volume ratio) so as to have 40% by mass of a solid content concentration to prepare a coating liquid.
Subsequently, the above coating liquid was applied onto the entire main surface on one side of the base material formed of a stainless steel sheet (SUS sheet) with a thickness of 0.5 mm to have a thickness of 250 μm by using a roll coater to form a rubber compound coating layer, and thereafter, heating treatment was applied at 120° C. for 10 minutes to evaporate toluene and ethyl acetate and dry it, whereby the rubber layer was fixed and formed. Thereafter, heating treatment was performed at 200° C. for 10 minutes, and thereby an intermediate material having the rubber layer with a thickness of 100 μm on the main surface on one side of the base material formed of an SUS sheet was obtained.
A stainless steel sheet (SUS sheet) with a thickness of 0.5 mm was bonded onto a rubber layer side of the obtained intermediate material, whereby the disc brake shim material (width 240 mm, length 15 mm, thickness 0.6 mm, porosity of the rubber layer 41%, closed cell rate of the rubber layer 37%) formed of a three-layer structure of the SUS sheet/rubber layer/SUS sheet was obtained.
The obtained disc brake shim material was provided for measurement of vibration dampening property evaluation similarly to example 1, as a test piece of the disc brake shim that is oriented to face the pad material at the time of arrangement.
A rubber compound formed from the components shown in Table 1, and compounded to contain 40% by mass of a polymer, a total of 3% by mass of a vulcanizing agent and a vulcanization accelerator, and 57% by mass of a filler was dissolved in a mixed liquid of toluene and ethyl acetate (toluene:ethyl acetate=70:30 in a volume ratio) so as to have 40% by mass of a solid content concentration to prepare a coating liquid.
Subsequently, the above described coating liquid was applied onto the entire main surface on one side of the base material formed of a stainless steel sheet (SUS sheet) with a thickness of 0.5 mm to have a thickness of 250 μm by using a roll coater to form a rubber compound coating layer, and thereafter heating treatment was applied thereto at 120° C. for 10 minutes to evaporate toluene and ethyl acetate and dry it, whereby the rubber layer was fixed and formed. Thereafter, heating treatment was performed at 200° C. for 10 minutes, and thereby the disc brake shim material (width 240 mm, length 15 mm, thickness 0.6 mm) having a solid rubber layer with a thickness of 100 μm on the main surface on one side of the base material formed of an SUS sheet was obtained.
A loss coefficient η was measured under the same conditions as in example 1, except that the obtained disc brake shim material was oriented so that the solid rubber layer abuts on the support stand of a stainless steel sheet with a thickness of 5 mm of the loss coefficient measuring device (MS18143 made by Bruel & Kjar Sound & Vibration Measurement A/S).
According to Table 1, the disc brake shim according to the present invention obtained in each of example 1 and example 2 has the base material layer formed of a metal sheet, and the rubber layer that is laminated and disposed on at least a part of the main surface on one side of the base material layer, contains pores derived from a plurality of hollow microcapsules inside, and has flexibility, whereby it is considered that the rubber layer deforms to follow vibration of the brake pads and the like to easily convert the vibration into thermal energy, and further the rubber layer can easily convert the vibration of the brake pads and the like into frictional heat because the rubber layer has a high friction coefficient, so that it is found that excellent braking performance (vibration dampening performance) is shown under the above described temperatures, and occurrence of squeal is favorably suppressed.
In contrast to the above, according to Table 1, it is found that the disc brake shim obtained in comparative example 1 has the base material layer formed of a metal sheet, and the solid rubber layer that is laminated and disposed on the main surface on one side of the base material layer to be the outermost layer at the time of arrangement, and therefore the loss coefficient is low in the range of all the temperatures of measurement, so that under these temperatures, the disc brake shim is inferior in braking performance, and cannot suppress occurrence of squeal.
According to the present invention, it is possible to provide a novel disc brake shim and disc brake that can effectively suppress occurrence of vibration and squeal, is easy to manufacture and has excellent quality stability.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-213389 | Dec 2020 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2021/046209 | 12/15/2021 | WO |
