Wiper blade rubber

Abstract

The neck stiffness, which is the load just before the shoulder portion (11b) contacts the mounting and holding portion (12), is 43 mN / cm or more and 67 mN / cm or less. Furthermore, when the tip sliding portion (11a) is brought into contact with the glass surface of the glass disc 21 on a rotating disc testing machine while the mounting and holding portion (12) is held, and a load of 40 g / cm is applied, the angle α1 between the horizontal line La on the glass surface and the parallel line Lb of the straight portion of the tip sliding portion 11a, and the angle α2 between the horizontal line La on the glass surface and the parallel line Lc of the straight portion of the lip portion 11 at an intermediate position between the tip sliding portion 11a and the shoulder portion 11b, are such that α2-α1 is 7 deg or more and 30 deg or less. This improves the reversibility and allows the lip portion to flex, thereby preventing the generation of abnormal noise during reversal.

Description

Technical Field

[0001] The present invention relates to a wiper blade rubber used for a windshield of an automobile or the like.

Background Art

[0002] Conventionally, for example, as in Patent Document 1, there is known a blade rubber for wiping a window surface by the reciprocating swing of a wiper arm. This blade rubber has a shape with a substantially constant cross-section in the longitudinal direction, and includes a mounting and holding portion for mounting to a lever body, a lip portion for wiping the window surface, and a neck portion for connecting these mounting and holding portion and the lip portion.

[0003] At least the neck portion of this blade rubber is subjected to a curing treatment by irradiation with a curing acceleration source. In this curing treatment, the absorbed dose is the largest at the portion corresponding to the support by the lever body, and different in the longitudinal direction so that the intermediate portion between adjacent support corresponding portions has the smallest absorbed dose, and thus a changed curing treatment is performed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the wiper blade rubber of Patent Document 1, since a curing treatment that varies in the longitudinal direction is performed, the curing treatment work is relatively troublesome.

[0006] The present disclosure has been made in view of such points, and an object thereof is to prevent the generation of abnormal noise during inversion by improving the reversibility and making the lip portion compliant.

Means for Solving the Problems

[0007] To achieve the above objective, this disclosure provides the wiper blade rubber with a uniform, predetermined rigidity along its longitudinal direction.

[0008] Specifically, in the first embodiment, A lip portion with a triangular cross-section having a tip sliding portion that contacts and slides against the glass surface and a shoulder portion that gradually widens from the tip sliding portion, A mounting and holding part that is held by the wiper holding part, The subject is a wiper blade rubber having a thin-walled neck portion connecting the shoulder portion and the mounting and holding portion, and this wiper blade rubber is In a surface properties measuring instrument, The mounting jig holds the mounting and holding portion of the wiper blade rubber, which has been cut to a predetermined length. The mounting jig is moved relative to the load cell at a speed of 10 mm / min, and the tip range of 10% of the lip length from the tip sliding portion to the shoulder portion is brought into contact with the load cell. The neck stiffness, which is the load just before the shoulder portion contacts the mounting holding portion, is 43 mN / cm or more and 67 mN / cm or less, When the mounting and holding portion is held in place and the tip sliding portion is brought into contact with the glass surface of the glass on a rotating disc testing machine, and a load of 40 g / cm is applied, the wiper blade rubber, when viewed from the longitudinal direction, The angle α1 between the horizontal line of the glass surface and the parallel line of the straight portion of the tip sliding part, The angle α2 between the horizontal line of the glass surface and the parallel line of the straight portion at an intermediate position on the shoulder side of the tip sliding portion of the lip portion, The distance between α2 and α1 is between 7 degrees and 30 degrees.

[0009] If the neck stiffness is made less than 43 mN / cm, the lip becomes too soft, impairing its reversibility and generating abnormal noise. Conversely, if it is made more than 67 mN / cm, the lip becomes too hard, impairing its reversibility and generating abnormal noise. However, by keeping it between 43 mN / cm and 67 mN / cm, the generation of abnormal noise is suppressed without changing the neck stiffness in the longitudinal direction of the lip. Furthermore, if α2-α1 becomes less than 7 degrees, the lip becomes hard, impairing its reversibility and generating abnormal noise. While it is difficult to make it greater than 30 degrees due to constraints on the shape of the lip, keeping it between 7 degrees and 30 degrees allows for the suppression of abnormal noise with an appropriate lip shape. The surface properties measuring instrument is not particularly limited, but an example is the surface properties measuring instrument manufactured by Shinto Kagaku Co., Ltd.

[0010] In the second embodiment, in the first embodiment, The polymer is natural rubber or a blend of natural rubber and chloroprene rubber, and the rubber composition contains carbon black.

[0011] According to the above configuration, a wiper blade rubber with excellent wiping properties can be obtained.

[0012] In the third aspect, in the second aspect, At least the lip portion is provided with a graphite coating layer.

[0013] According to the above configuration, a wiper blade rubber with excellent wiping properties can be obtained.

[0014] In the fourth aspect, in the third aspect, At least the lip portion has a chlorine-treated film of 1.0 μm to 2.0 μm thickness formed beneath the coating layer.

[0015] When the thickness of the chlorine film is less than 1.0 μm, the neck rigidity decreases. When it is more than 2.0 μm, the neck rigidity becomes too high or the lip part becomes too hard. However, by setting the thickness to be 1.0 μm or more and 2.0 μm or less, appropriate neck rigidity and the flexibility of the lip part can be obtained.

[0016] In the fifth aspect, in any one of the first to fourth aspects, After applying a tensile force and stretching it to 100%, the operation of returning it to 0% is repeated three times. At the third time, the 30% modulus is 0.6 MPa or more and 1.2 MPa or less.

[0017] When the 30% modulus is less than 0.6 MPa, the reversibility deteriorates. Also, when it is more than 1.2 MPa, the reversibility deteriorates. However, by setting it to be 0.6 MPa or more and 1.2 MPa or less, the reversibility is improved and water streaking is less likely to occur.

Advantages of the Invention

[0018] As described above, according to the present disclosure, by increasing the neck rigidity of the wiper blade rubber, the reversibility can be improved, and by making the lip part moderately flexible, the generation of abnormal noise during reversal can be suppressed.

Brief Description of the Drawings

[0019] [Figure 1] It is a cross-sectional view showing a state of measuring the contact angle of the wiper blade rubber. [Figure 2] It is an enlarged front view of part II in FIG. 3. [Figure 3] It is a front view showing a state of measuring the neck rigidity of the wiper blade rubber. [Figure 4] It is a table comparing the examples and comparative examples of the present disclosure.

Modes for Carrying Out the Invention

[0020] Hereinafter, embodiments of the present disclosure will be described based on the drawings.

[0021] This is a cross-sectional view showing how the contact angle of the wiper blade rubber 10 is measured. The wiper blade rubber 10 is a generally flat, elongated rubber component, and has a triangular cross-section lip portion 11 having a tip sliding portion 11a that contacts and slides on the glass surface and a shoulder portion 11b that gradually widens from the tip sliding portion 11a, a mounting and holding portion 12 that is held by the wiper holding portion of a wiper arm (not shown), and a thin-walled neck portion 13 that connects the shoulder portion 11b and the mounting and holding portion 12.

[0022] In this embodiment, the wiper blade rubber 10 has a mounting and holding portion 12 that is attached to and held by a vertebra of a wiper drive unit provided, for example, on the lower side of the windshield of an automobile. When the wiper drive unit is driven, the lip portion 11 tilts with the neck portion 13 as a pivot point and slides in contact with the surface of the windshield, thereby wiping away rain and the like.

[0023] The wiper blade rubber 10 according to this embodiment is formed from a crosslinked rubber composition containing a rubber component and a rubber compounding agent.

[0024] Examples of rubber components include natural rubber (NR), chloroprene rubber (CR), ethylene propylene diene rubber (EPDM), and styrene butadiene rubber (SBR). Examples of CR include sulfur-modified type, mercaptan-modified type, and xanthogene-modified type. The rubber component preferably contains one or more of these, and a blended rubber containing NR and CR is preferably used from the viewpoint of obtaining excellent wiping properties.

[0025] When the rubber component is a blend rubber containing NR and CR, the NR content is preferably greater than the CR content from the viewpoint of obtaining excellent wiping properties.

[0026] Examples of rubber compounding agents include carbon black, vulcanization accelerators, processing aids, vulcanization accelerators, and antioxidants.

[0027] Examples of carbon black include channel black, furnace black, thermal black, and acetylene black. Examples of furnace black include SAF, ISAF, N-339, HAF, N-351, MAF, FEF, SRF, GPF, ECF, and N-234. Examples of thermal black include FT and MT. It is preferable that the carbon black contains one or more of these types.

[0028] The wiper blade rubber 10 according to this embodiment can be manufactured by preparing an uncrosslinked rubber composition by mixing a rubber compound containing carbon black and a crosslinking agent with the rubber component and kneading it, and then molding and crosslinking this uncrosslinked rubber composition. Examples of molding methods include press molding, extrusion molding, injection molding, and transfer molding.

[0029] In the wiper blade rubber 10 according to this embodiment, the entire surface is subjected to a chlorine treatment. From the viewpoint of obtaining a wiper blade rubber 10 with excellent wiping properties, a chlorine-treated chlorine film of 1.0 μm to 2.0 μm in thickness is formed. The chlorine film only needs to be applied to at least the lip portion 11, but usually it is applied to most of the surface of the wiper blade rubber 10. The chlorine treatment may be carried out by treatment using, for example, bleaching powder or trichloroisocyanuric acid.

[0030] In the wet chlorination method, the blade rubber body is first immersed in a chlorine-containing chlorine-treated aqueous solution. Examples of chlorine-treated aqueous solutions include aqueous solutions of hypochlorous acid or hypochlorites (such as calcium hypochlorite or sodium hypochlorite) to which an acid such as hydrochloric acid is added to lower the pH and generate chlorine.

[0031] The chlorine concentration in the chlorinated aqueous solution is preferably 100 ppm to 800 ppm, more preferably 150 ppm to 700 ppm. The pH of the chlorinated aqueous solution is preferably 1.5 to 2.4, more preferably 1.8 to 2.3.

[0032] Next, the blade rubber body, which has been removed from the chlorinated aqueous solution, is immersed in washing water to effectively stop the chlorination reaction.

[0033] Next, the blade rubber body, which has been removed from the washing water, is immersed in warm water for cleaning.

[0034] Then, the wiper blade rubber 10 is obtained by drying the blade rubber body that has been removed from the hot water.

[0035] In the above embodiment, the entire surface of the wiper blade rubber 10 is subjected to chlorination treatment, but the invention is not limited to this configuration, and it is sufficient if the treatment is applied to at least the surface of the lip portion 11 that constitutes the contact sliding portion with other members.

[0036] Furthermore, in order to obtain a wiper blade rubber 10 with excellent wiping properties, at least the lip portion 11 is provided with a graphite coating layer.

[0037] The coating agent for forming the coating layer comprises a solid lubricant and a binder for adhering the solid lubricant to the surface of the wiper blade rubber 10. The binder is, for example, an acrylic resin. The acrylic resin preferably has amino groups in its side chains. Furthermore, the amino groups are preferably primary amino groups.

[0038] As solid lubricants, graphite, molybdenum disulfide, tungsten disulfide, boron nitride, polytetrafluoroethylene (PTFE), etc. can be used, with graphite being preferred.

[0039] - Flex measurement - A 100 mm long test piece was cut from the wiper blade rubber 10. The mounting and holding part 12 of this test piece was attached to a long, narrow fixing jig 20 as shown in Figure 1, and the fixing jig 20 with the test piece attached was pressed against a glass disc 21. Water W was sprayed onto the glass disc 21 to wet it, and the glass disc 21 was rotated so that the tip of the test piece was moving at 1.27 m / s, causing the test piece to slide on the glass disc 21.

[0040] In this state, when a load of 40 g / cm was applied, the angle α1 between the horizontal line La on the glass surface and the parallel line Lb of the straight portion of the tip sliding part 11a, and the angle α2 between the horizontal line La on the glass surface and the parallel line Lc of the straight portion at an intermediate position on the lip part 11 closer to the shoulder part 11b than the tip sliding part 11a were photographed with a digital camera, and the value of α2 - α1 was calculated by reading the photographic data into software with a plane measurement function.

[0041] In this embodiment, the distance between α2 and α1 is preferably between 7 degrees and 30 degrees.

[0042] -Neck stiffness measurement- As shown in Figure 3, a surface quality measuring instrument 1 manufactured by Shinto Kagaku Co., Ltd. is used, which has a horizontally movable stage 2 and a load cell 5.

[0043] As shown in an enlarged view in Figure 2, the mounting jig 3 fixed on the stage 2 holds the mounting and holding portion 12 of the wiper blade rubber 10, which has been cut to a predetermined length. The length of the wiper blade rubber 10 during measurement is not limited to 3 cm; it can be adjusted to a length suitable for the measuring equipment.

[0044] Next, by moving stage 2 horizontally, the mounting jig 3 is moved at a speed of 10 mm / min relative to the load cell 5 which is not on stage 2.

[0045] Next, the tip range, which is 10% of the lip length from the tip sliding portion 11a to the shoulder portion 11b, is brought into contact with the height-adjustable contact portion 4 connected to the load cell 5.

[0046] The neck stiffness was defined as the load just before the neck portion 13 bends and the shoulder portion 11b contacts the mounting and holding portion 12.

[0047] In this embodiment, it is desirable that the neck stiffness per unit length be between 43 mN / cm and 67 mN / cm.

[0048] - Repeated tensile testing - Using a tensile testing machine (not shown), the rubber on the back of the wiper blade rubber 10 is cut out, and the protrusions remaining on the cut side are removed by polishing to create a 100 mm long test piece. A tensile force is then applied to the test piece, which is stretched to 100%, and then returned to 0%, and this process is repeated three times.

[0049] Then, on the third attempt, the 30% modulus is measured, which represents the force that tries to return the specimen to its original shape when its elongation is 30%.

[0050] In this embodiment, the wiper blade rubber 10 is preferably 0.6 MPa or more and 1.2 MPa or less.

[0051] -Inversion Measurement- Although not shown in detail in the diagram, the evaluation is performed in an actual vehicle by setting the arm pressure on the wiper arm to which the wiper blade rubber 10 is attached to 15 gf / cm and driving the wiper with a water spray rate of 800 ml / min or more.

[0052] If the water runoff on the glass surface was 50mm or less, it was marked as "○" (correct); if it exceeded 50mm, it was marked as "×" (incorrect).

[0053] -Noise Measurement- Similarly, in an actual vehicle, the arm pressure on the wiper arm to which the wiper blade rubber 10 is attached is set to 15 gf / cm, and the wiper is driven with a water spray rate of 800 ml / min or more for evaluation.

[0054] If there was no abnormal noise, it was marked with a ○; if there was abnormal noise, it was marked with a ×. Then, based on an overall assessment of inversion properties and abnormal noise, the embodiment that was more preferable than the ○ embodiment was marked with a ◎.

[0055] -Chlorine film thickness measurement- A test specimen of the wiper blade rubber 10 was observed using a scanning electron microscope (SEM) at the tip sliding portion 11a of the lip portion 11, and the thickness of the chlorine film formed on the tip sliding portion 11a was measured.

[0056] -Lip thickness measurement- The lip thickness at the tip sliding portion 11a of the wiper blade rubber 10 was measured using an image dimension measuring device.

[0057] Figure 4 shows the results of the measurements described above for Examples 1-7 and Comparative Examples 1-6.

[0058] <Example 1> With a lip thickness of 0.60 mm, neck radius of 0.2 mm, chlorine film thickness of 1.8 μm, M30 of 1.00 MPa, neck rigidity of 45 mN / cm, and flex of 12.1 degrees, the reversal was good, no abnormal noise was generated, and the results were more favorable.

[0059] <Example 2> With a lip thickness of 0.58 mm, neck radius of 0.2 mm, chlorine film thickness of 1.6 μm, M30 of 1.10 MPa, neck rigidity of 53 mN / cm, and flex of 14.7 degrees, the reversal was good, no abnormal noise was generated, and the results were more favorable.

[0060] <Example 3> With a lip thickness of 0.59 mm, neck radius of 0.2 mm, chlorine film thickness of 1.1 μm, M30 of 1.14 MPa, neck rigidity of 63 mN / cm, and flex of 22.4 degrees, the reversal was good, no abnormal noise was generated, and the results were more favorable.

[0061] <Example 4> The lip thickness was 0.61 mm, the neck radius was 0.2 mm, the chlorine film thickness was 2.0 μm, the M30 was 0.90 MPa, the neck rigidity was 47 mN / cm, and the flex was 7.0 degrees. It also had good reversal properties and did not produce any abnormal noise.

[0062] <Example 5> The lip thickness was 0.60 mm, the neck radius was 0.2 mm, the chlorine film thickness was 2.0 μm, the M30 pressure was 1.20 MPa, the neck rigidity was 67 mN / cm, and the flex was 7.0 degrees. It also had good reversal properties and did not produce any abnormal noise.

[0063] <Example 6> The lip thickness was 0.58 mm, the neck radius was 0.2 mm, the chlorine film thickness was 1.1 μm, the M30 was 0.60 MPa, the neck rigidity was 43 mN / cm, and the flex was 30.0 deg. It also had good reversal properties and did not produce any abnormal noise.

[0064] <Example 7> The lip thickness was 0.58 mm, the neck radius was 0.3 mm, the chlorine film thickness was 1.0 μm, the M30 pressure was 1.14 MPa, the neck rigidity was 67 mN / cm, and the flex was 30.0 deg. It also had good reversal properties and did not produce any abnormal noise.

[0065] <Comparative Example 1> The lip thickness was 0.65 mm, the neck radius was 0.2 mm, the chlorine film thickness was 2.0 μm, the M30 pressure was 0.50 MPa, the neck rigidity was 38 mN / cm, and the flex was 7.0 degrees. It had poor reversal properties and produced abnormal noises.

[0066] <Comparative Example 2> The lip thickness was 0.58mm, the neck radius was 0.2mm, the chlorine film thickness was 0.9μm, the M30 pressure was 0.55MPa, the neck rigidity was 35mN / cm, and the flex was 4.3deg. It had poor reversal properties and produced abnormal noises.

[0067] <Comparative Example 3> The lip thickness was 0.56 mm, the neck radius was 0.3 mm, the chlorine film thickness was 1.0 μm, the M30 pressure was 1.30 MPa, the neck rigidity was 77 mN / cm, and the flex was 5.7 degrees. No abnormal noise was produced, but the reversal performance was poor and the water pull exceeded 50 mm.

[0068] <Comparative Example 4> The lip thickness was 0.60 mm, the neck radius was 0.2 mm, the chlorine film thickness was 2.3 μm, the M30 pressure was 1.20 MPa, the neck rigidity was 70 mN / cm, and the flex was 5.0 deg. While the reversal was relatively good, an abnormal noise occurred.

[0069] <Comparative Example 5> The lip thickness was 0.56 mm, the neck radius was 0.2 mm, the chlorine film thickness was 0.3 μm, the M30 pressure was 1.15 MPa, the neck rigidity was 63 mN / cm, and the flex was 37.0 deg. No abnormal noise was produced, but the inversion performance was poor and the water pull exceeded 50 mm.

[0070] <Comparative Example 6> The lip thickness was 0.57 mm, the neck radius was 0.2 mm, the chlorine film thickness was 0.4 μm, the M30 pressure was 0.53 MPa, the neck rigidity was 33 mN / cm, and the flex was 35.0 deg. No abnormal noise was produced, but the reversal performance was poor and the water pull exceeded 50 mm.

[0071] As can be seen from the comparison between the example and the comparative example above, if the neck rigidity is made less than 43 mN / cm, the neck portion 13 becomes too soft, worsening its inversion properties and generating abnormal noise. Conversely, if it is made greater than 67 mN / cm, the neck portion 13 becomes too hard, worsening its inversion properties and generating abnormal noise. However, by setting it between 43 mN / cm and 67 mN / cm, the generation of abnormal noise is suppressed without changing the neck rigidity in the longitudinal direction of the lip portion 11. Furthermore, if α2-α1 becomes less than 7 deg, the inversion properties worsen and abnormal noise is generated. While it is difficult to make it greater than 30 deg due to the constraints of the shape of the lip portion 11, setting it between 7 deg and 30 deg allows for the suppression of abnormal noise with an appropriate shape for the lip portion 11.

[0072] Furthermore, if the thickness of the chlorine film is made thinner than 1.0 μm, the neck rigidity decreases, and if it is made thicker than 2.0 μm, the neck rigidity becomes too high or the lip portion 11 becomes too stiff. However, by setting the thickness to between 1.0 μm and 2.0 μm, an appropriate balance of neck rigidity and flexibility of the lip portion 11 can be obtained.

[0073] Furthermore, if the 30% modulus is less than 0.6 MPa, the reversal properties deteriorate, and if it is greater than 1.2 MPa, the reversal properties deteriorate. However, if it is between 0.6 MPa and 1.2 MPa, the reversal properties improve and water drainage is less likely to occur.

[0074] Therefore, according to the wiper blade rubber 10 of this embodiment, the reversal ability can be improved by increasing the neck rigidity, and the generation of abnormal noise during reversal can be suppressed by allowing the lip portion 11 to flex appropriately.

[0075] The embodiments described above are essentially preferred examples and are not intended to limit the scope of the present invention, its applications, or uses. [Explanation of Symbols]

[0076] 10 Wiper Blade Rubber 11 Lip section 11a Tip sliding part 11b Shoulder section 12 Mounting and holding part 13. Neck section 20 Fixing fixtures 21 Glass Disc

Claims

1. A lip portion with a triangular cross-section having a tip sliding portion that contacts and slides against the glass surface and a shoulder portion that gradually widens from the tip sliding portion, A mounting and holding part that is held by the wiper holding part, A wiper blade rubber having a thin-walled neck portion connecting the shoulder portion and the mounting and holding portion, In a surface properties measuring instrument, The mounting jig holds the mounting and holding portion of the wiper blade rubber, which has been cut to a predetermined length. The mounting jig is moved relative to the load cell at a speed of 10 mm / min, and the tip range of 10% of the lip length from the tip sliding portion to the shoulder portion is brought into contact with the load cell. The neck stiffness, which is the load just before the shoulder portion contacts the mounting holding portion, is 43 mN / cm or more and 67 mN / cm or less, When the mounting and holding portion is held in place, and the tip sliding portion is brought into contact with the glass surface of the glass on the rotating disc testing machine, and a load of 40 g / cm is applied, the wiper blade rubber, when viewed from the longitudinal direction, The angle α1 between the horizontal line of the glass surface and the parallel line of the straight portion of the tip sliding part, The angle α2 between the horizontal line of the glass surface and the parallel line of the straight portion at an intermediate position on the shoulder side of the tip sliding portion of the lip portion, The α2-α1 interval is between 7 deg and 30 deg. A wiper blade rubber characterized by the following features.

2. The polymer is natural rubber or a blend of natural rubber and chloroprene rubber, and the composition is a rubber composition containing carbon black. The wiper blade rubber according to feature 1.

3. At least the lip portion is provided with a graphite coating layer. The wiper blade rubber according to feature 2.

4. At least the lip portion has a chlorine-treated film of 1.0 μm to 2.0 μm thickness formed beneath the coating layer. The wiper blade rubber according to feature 3.

5. After printing a tensile force and stretching it to 100%, repeat the process of returning it to 0% three times. On the third measurement, the 30% modulus is between 0.6 MPa and 1.2 MPa. A wiper blade rubber according to any one of claims 1 to 4.

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