Air intake filter for air compressor

Abstract

To provide an air intake filter for an air compressor capable of suppressing deposition of powder dust and restricting clogging, thereby solving the problem, in a conventional air intake filter for an air compressor, that it is difficult to suppress deposition of powder dust itself, and consequently, that there is room for improvement of a countermeasure against clogging in a filter for air intake.SOLUTION: In an air intake side region 40a of a filter 40 (air intake side filter 41) for an air compressor 1, density is higher than that in an exhaust side region 40b (exhaust side filter 42).SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present disclosure relates to an intake filter for an air compressor used in an air compressor that supplies compressed air to pneumatic tools such as compressed air-driven nailers and air dusters. [Background technology]

[0002] Patent Document 1 discloses technology related to an air compressor. The air compressor has a reciprocating compression mechanism that generates compressed air. The compression mechanism converts the rotational output of an electric motor into reciprocating motion of a piston in a cylinder using a crank mechanism. Compressed air is generated by compressing outside air with the piston. The compressed air generated by the compression mechanism is stored in a tank. The compressed air stored in the tank is supplied to air tools such as compressed air-driven nailers and air dusters.

[0003] Outside air for generating compressed air is drawn into a crankcase that houses a crank mechanism. An anti-dust intake filter is installed in the intake path of the outside air to the crankcase. According to Patent Document 1, the filter case is attached to the outer surface of a crankcase cover that airtightly closes the end of the crankcase. The crankcase cover is provided with a plurality of intake holes that penetrate from the inside to the outside. The intake filter covers the plurality of intake holes from the outside. The intake filter is held by a filter cover that is joined to the crankcase cover. A gap that allows outside air to be drawn in is provided between the periphery of the crankcase and the periphery of the filter cover. The outside air drawn in through the gap has dust filtered out by the filter before being introduced into the crankcase.

[0004] When an air compressor is used repeatedly, dust accumulates on the surface of the intake side of the intake filter. When the intake filter becomes clogged with dust, the breathability of the intake filter is impaired. Patent Document 2 discloses an intake mechanism in which multiple intake filters with different mesh sizes are arranged in the thickness direction. When some of the intake filters become clogged, only the clogged intake filters can be replaced. This allows the breathability of the intake filter to be maintained. However, with conventional intake filters for air compressors, it was difficult to prevent dust from accumulating. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5186799 [Patent Document 2] JP 2007-23851 A Summary of the Invention [Problem to be solved by the invention]

[0006] Conventional air compressor intake filters have room for improvement in terms of preventing clogging. Therefore, there is a need for an air compressor intake filter that can suppress the accumulation of dust and prevent clogging. [Means for solving the problem]

[0007] According to one feature of the present disclosure, the intake side region of the air compressor intake filter has a higher density than the exhaust side region, which prevents dust from entering the high-density intake side region from the surface of the intake side region, thereby preventing dust from accumulating in the intake side region and preventing clogging of the intake filter. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is an external perspective view of an air compressor. [Diagram 2]This is a view taken along the line II in Figure 1. This figure is a perspective view of the air compressor as seen from the left rear. This figure shows the state in which the main body cover has been removed to expose the compression mechanism. [Diagram 3] FIG. 2 is a cross-sectional view of the compression mechanism. [Figure 4] FIG. 2 is a perspective view of an intake section according to the present embodiment. [Diagram 5] FIG. [Figure 6] 4 is an exploded perspective view of the filter, the filter cover, and the dust cover as viewed from the inside. FIG. [Figure 7] 7 is a cross-sectional view taken along line VII-VII in FIG. 3, and is a vertical cross-sectional view of the intake portion. [Figure 8] 8 is a cross-sectional view taken along line VIII-VIII in FIG. 5, and is a vertical cross-sectional view of the intake portion. [Figure 9] IX-IX line cross-sectional view of FIG. 5, and is a vertical cross-sectional view of the intake portion. [Figure 10] FIG. 8 is a partial enlarged view of part X in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] According to another feature of the present disclosure, the surface roughness of the intake side of the air compressor intake filter is smaller than the surface roughness of the exhaust side. Therefore, dust can be prevented from accumulating on the intake side. Even if dust adheres to the intake side, the dust can be easily peeled off from the intake side having a smaller surface roughness by, for example, the wind blown toward the intake filter by the intake fan of the air compressor. Therefore, clogging of the intake side of the intake filter can be prevented.

[0010] According to another feature of the present disclosure, the intake side region of the intake filter for an air compressor is made of felt made of chemical fiber. The exhaust side region of the intake filter is made of felt containing animal fiber. Therefore, the intake side region is not easily altered by heating, pressurization, etc. Therefore, the intake side region can be processed to suppress the accumulation of dust while maintaining the breathability of the intake side region. On the other hand, the exhaust side region is made of felt containing animal fiber that is widely used in conventional intake filters for air compressors. Therefore, the exhaust side region can be provided with the same degree of breathability as conventional intake filters. Thus, the accumulation of dust in the intake side region of the intake filter can be suppressed while maintaining breathability.

[0011] According to another feature of the present disclosure, the chemical fiber in the intake side region is made of polyester. Therefore, polyester chemical fiber is relatively inexpensive. Moreover, by processing the polyester chemical fiber by heating, pressing, etc., the dust peeling property can be improved. Therefore, clogging due to accumulation of dust in the intake side region can be suppressed.

[0012] According to another feature of the present disclosure, the animal fiber of the exhaust side region is wool. Therefore, the exhaust side region is made of wool felt, which can be processed with good dimensional accuracy. Therefore, it is possible to prevent a gap that allows dust to enter between the intake filter housing and the exhaust side region from being formed. This improves the filter performance of the intake filter.

[0013] According to another feature of the present disclosure, the intake side region has an intake side surface that is surface-treated to reduce surface roughness. By reducing the surface roughness of the intake side surface, therefore, it is possible to enhance the detachment of dust from the intake side surface.

[0014] Another feature of the present disclosure relates to a manufacturing method for an intake filter for an air compressor. The surface of the intake side area is heated and pressurized to form a surface-treated intake side. Therefore, the surface roughness of the intake side can be reduced by a simple surface treatment process of heating and pressing. This makes it possible to reduce the manufacturing cost of an intake filter with an intake side that has high dust releasability.

[0015] According to another feature of the present disclosure, the intake side region is made of a different material than the exhaust side region. The intake side region is thinner than the exhaust side region. Therefore, the accumulation of dust can be suppressed in the thinner intake side region, and the exhaust side region, which occupies more than half of the intake filter, can ensure the same level of breathability as a conventional intake filter. This makes it possible to counter clogging of the intake filter while ensuring good breathability.

[0016] According to another feature of the present disclosure, the intake side region and the exhaust side region are bonded to each other by a mesh-like adhesive, so that the intake side region and the exhaust side region can be bonded to each other without impairing the breathability of the intake filter.

[0017] According to another feature of the present disclosure, there is provided a filter cover that covers the intake filter from the intake side. The filter cover has a dust outlet that opens downward when attached to the compressor body. Therefore, dust that has peeled off and fallen from the intake side area of ​​the intake filter can be quickly discharged from the dust outlet to the outside of the filter cover. This makes it possible to prevent dust from accumulating inside the filter cover.

[0018] According to another feature of the present disclosure, the filter cover is attached to the compressor body in a position extending in the vertical direction. The filter cover has a plurality of dust exhaust ports on its outer periphery. At least one of the plurality of dust exhaust ports opens downward. Therefore, the filter cover has at least one dust exhaust port opening downward in any of a plurality of positions in which the filter cover extends in the vertical direction. Therefore, the filter cover can be attached to the compressor body without being concerned about the vertical orientation of the filter cover. This can improve the ease of assembly of the filter cover.

[0019] Next, an embodiment of the present disclosure will be described with reference to Figs. 1 to 10. As shown in Figs. 1 and 2, an air compressor 1 has two cylindrical tanks 2 that are long in the front-rear direction. The generated compressed air is stored in the two tanks 2. A total of four legs 3 are provided in front and behind the two tanks 2. Each leg 3 is made of a rubber material with high vibration resistance. Side protectors 3a are provided in parallel on each leg 3. A drain cock 2a for draining water is provided between the front parts of the two tanks 2. The upper parts of the two tanks 2 are connected to each other by a base part 4. A compression mechanism 10 is mounted on the upper surface of the base part 4. A handle part 5 for carrying is attached to the front and rear of the base part 4, straddling the upper parts of the two tanks 2. Fig. 1 shows the compression mechanism 10 covered with a main body cover 6.

[0020] As shown in FIG. 1, two high-pressure outlets 7 and two low-pressure outlets 8 are arranged on the left and right sides of the front of the body cover 6. Compressed air of, for example, 2.5 MPa is supplied from the high-pressure outlet 7. Compressed air of, for example, 1 MPa is supplied from the low-pressure outlet 8. Adjustment dials 7a and 8a for setting the discharge pressure are provided above the outlets 7 and 8, respectively. An operation unit 9 including various display units and mainly used for startup operations is provided on the front upper surface of the body cover 6. A plurality of air vents 6a are provided on the front, rear, left and right sides of the body cover 6 in a mesh pattern (the air vents 6a on the rear side of the body cover 6 are not visible in FIG. 1).

[0021] The compression mechanism 10 is exposed when the main body cover 6 is removed as shown in Fig. 2. As shown in Figs. 2 and 3, the compression mechanism 10 has a first compression section 11 at the front of a cylindrical crankcase 21, and a second compression section 12 at the rear. An electric motor 22 is supported on the right side of the crankcase 21 between the first compression section 11 and the second compression section 12. The crankcase 21 is fixed onto the base section 4.

[0022] As shown in Figs. 2 and 3, the electric motor 22 is a brushless motor that can obtain a relatively large starting torque. The electric motor 22 has a rotor 22a in an annular shape and a stator 22b in an annular shape located on the inner periphery of the rotor 22a. The stator 22b is fixed to the right side of the crankcase 21. A motor shaft 25 is connected to the center of the rotor 22a. A heat dissipation fan 23 is connected to the right end of the motor shaft 25. The heat dissipation fan 23 is connected to the right end of the motor shaft 25. The rotation of the heat dissipation fan 23 dissipates heat generated by the electric motor 22, thereby cooling the electric motor 22. The motor shaft 25 extends leftward through the center of the stator 22b. The motor shaft 25 is supported rotatably between the right and left sides of the crankcase 21 via a right bearing 25a and a left bearing 25b. The left end of the motor shaft 25 protrudes rightward through an intake section 30. An intake fan 24 is attached to the right end of the motor shaft 25. As the intake fan 24 rotates, outside air is blown into the intake section 30 .

[0023] 3, a first cylinder 11a of the first compression section 11 is connected to the front part of a cylindrical crankcase 21. A second cylinder 12a of the second compression section 12 is connected to the rear part of the crankcase 21. The inside of the crankcase 21 is connected to the outside air.

[0024] 3, a first piston 11b is accommodated in a first cylinder 11a so as to be capable of reciprocating back and forth. The first cylinder 11a extends forward from the front part of the crankcase 21. The first piston 11b is connected to a first crank portion 26 of a motor shaft 25 via a first rod 11c.

[0025] 3, a second piston 12b is accommodated in the second cylinder 12a so as to be capable of reciprocating back and forth. The second cylinder 12a extends rearward from the rear portion of the crankcase 21. The second piston 12b is connected to a second crank portion 27 of the motor shaft 25 via a second rod 12c.

[0026] As shown in Fig. 3, the first crank portion 26 and the second crank portion 27 are eccentric in the same direction at the same position around the axis of the motor shaft 25. Therefore, one rotation of the motor shaft 25 simultaneously performs a compression stroke of one of the first compression section 11 and the second compression section 12 and an intake stroke of the other. During a compression stroke in which the first piston 11b moves forward in the first compression section 11, the second piston 12b moves forward in the second compression section 12 to perform an intake stroke. During an intake stroke in which the first piston 11b moves rearward in the first compression section 11, the second piston 12b moves rearward in the second compression section 12 to perform a compression stroke.

[0027] As shown in Fig. 3, the first compression chamber 11d of the first cylinder 11a and the second compression chamber 12d of the second cylinder 12a are communicated with each other via a supply pipe 13 (see Fig. 2). The upstream side of the supply pipe 13 is connected to the first compression chamber 11d via an auxiliary check valve 11e. The auxiliary check valve 11e prevents compressed air from flowing back from the supply pipe 13 to the first compression chamber 11d. The downstream side of the supply pipe 13 is connected to the second compression chamber 12d. The compressed air that flows from the first compression chamber 11d into the supply pipe 13 via the auxiliary check valve 11e is supplied directly to the second compression chamber 12d.

[0028] In this way, by starting the electric motor 22, compressed air is generated in two stages, in the first compression section 11 and the second compression section 12. The compressed air supplied to the second compression chamber 12d of the second compression section 12 is compressed to a higher pressure as the second piston 12b moves backward. The compressed air generated in the second compression chamber 12d at a high pressure, for example, of about 4.5 MPa, flows into the air passage 15 leading to the tank 2 via the first check valve 14. The first check valve 14 prevents the compressed air that has flowed into the air passage 15 from flowing back into the second compression chamber 12d.

[0029] As shown in Figures 4 and 5, an intake section 30 is provided on the left side of the crankcase 21 of the compression mechanism 10. Outside air is introduced into the crankcase 21 through the intake section 30. Figures 4 and 5 show a state in which the intake fan 24 has been removed from the motor shaft 25. In Figures 7 to 9, outside air flows from left to right relative to the intake section 30 and is taken into the crankcase 21. Hereinafter, the upstream side of the intake air flow will also be referred to as the intake side (outside), and the downstream side will also be referred to as the exhaust side (inside).

[0030] As shown in FIG. 5, the intake section 30 includes a crankcase cover 31 that airtightly seals the intake opening 21a of the crankcase 21, a filter 40 that seals the inner intake hole 31e of the crankcase cover 31, a filter cover 33 that covers the filter 40, and a dust cover 34 that covers the filter cover 33.

[0031] 5 and 8, the opening 21a of the crankcase 21 is formed in a generally circular shape. The crankcase cover 31 is generally disk-shaped. The crankcase cover 31 is attached to the opening 21a of the crankcase 21 at its periphery with a total of six mounting screws 35. The opening 21a is air-tightly sealed by the crankcase cover 31. A cylindrical bearing recess 31a is provided in the center of the inner surface side of the crankcase cover 31. The bearing 25b is held in the bearing recess 31a.

[0032] 9, one regulating plate 25c is screwed to the opening side of the bearing recess 31a with four fixing screws 36. As a result, the opening side of the bearing recess 31a is closed by the regulating plate 25c. The bearing 25b is sandwiched between the bottom of the bearing recess 31a and the regulating plate 25c, thereby regulating the positional deviation of the bearing 25b in the direction of the motor axis J.

[0033] As shown in Figs. 5, 7 to 9, a filter accommodating recess 31b for accommodating a filter 40 is provided on the outer surface side of the crankcase cover 31. A cylindrical protrusion 31c for forming the bearing recess 31a on the inner surface side is provided at the center of the filter accommodating recess 31b. The motor shaft 25 is inserted into an insertion hole 31d provided at the center of the protrusion 31c. Screw holes 31g are provided at four equal positions on the periphery of the protrusion 31c. Fixing screws 36 for screwing the restricting plate 25c to the crankcase cover 31 are screwed into the screw holes 31g. The filter accommodating recess 31b is provided around the protrusion 31c.

[0034] As shown in Figures 5 and 8, a plurality of inner air intake holes 31e are provided in the bottom surface of the crankcase cover 31. As shown in Figures 5 and 7, a plurality of screw boss portions 31f are provided in the bottom surface of the crankcase cover 31. In this embodiment, four screw boss portions 31f are provided. A female screw portion 31h is provided on the inner periphery of each screw boss portion 31f. As will be described later, fixing screws 37 are fastened to the female screw portions 31h of the four screw boss portions 31f, respectively, whereby the filter cover 33 and the dust cover 34 are screwed to the crankcase cover 31 by so-called co-fastening.

[0035] As shown in FIG. 5, each screw boss 31f is provided on the outer surface of the crankcase cover 31 in a state of protruding to the left. The outer diameter of each screw boss 31f is stepped, with a large diameter portion on the base side and a small diameter portion on the tip side. Inside air intake holes 31e are provided on both sides of each screw boss 31f. In this embodiment, a total of eight inside air intake holes 31e are provided. One filter 40 is accommodated in the filter accommodating recess 31b so as to block the eight inside air intake holes 31e from the outside. The depth of the filter accommodating recess 31b is set to a depth that allows the filter 40 to be accommodated almost without excess or deficiency in the thickness direction. Therefore, as shown in FIGS. 7 to 9, the outer peripheral end surface of the crankcase cover 31 and the outer surface (intake side surface 41a) of the filter 40 are almost flush with each other.

[0036] 5 and 6, filter 40 is a sound-absorbing and dust-proof filter made of felt material and is formed in a generally circular plate shape. Filter 40 is composed of an intake-side filter 41 and an exhaust-side filter 42 that are stacked in the thickness direction (left-right direction). Intake-side filter 41 located on the intake side (outside) and exhaust-side filter 42 located on the exhaust side (inside) are provided with approximately the same shape and size when viewed from the direction of motor axis J.

[0037] 5 and 6, an insertion hole 41c is provided in the center of the intake-side filter 41, through which the protrusion 31c of the crankcase cover 31 is inserted, and insertion holes 41d are provided at four equal positions around the periphery of the insertion hole 41c, through which the screw holes 31g of the crankcase cover 31 are inserted. Insertion holes 41e are provided at four positions around the insertion hole 41c, through which the large diameter portion of the screw boss portion 31f of the crankcase cover 31 is inserted.

[0038] As shown in Figs. 5 and 6, an insertion hole 42c is provided at the center of the exhaust filter 42, through which the protrusion 31c of the crankcase cover 31 is inserted, and insertion holes 42d are provided at the four equal positions around the insertion hole 42c, through which the screw hole 31g of the crankcase cover 31 is inserted. At four positions around the insertion hole 42c, insertion holes 42e are provided for inserting the large diameter portion of the screw boss portion 31f of the crankcase cover 31. The insertion holes 41c, 41d, and 41e of the intake filter 41 are provided with approximately the same shape and size as the insertion holes 42c, 42d, and 42e of the exhaust filter 42. The insertion holes 41c, 41d, and 41e communicate with the insertion holes 42c, 42d, and 42e, respectively, when the intake filter 41 and the exhaust filter 42 are arranged in the thickness direction (see Figs. 7 and 9).

[0039] As shown in Figs. 5 to 9, the intake side filter 41 is provided in an intake side region 40a of a predetermined thickness from the intake side surface 41a. The thickness of the intake side filter 41 (intake side region 40a) is, for example, 40% or less, 30% or less, and preferably 20% or less of the entire thickness of the filter 40. The thickness of the intake side filter 41 is, for example, 1.5 mm. The exhaust side filter 42 is provided in an exhaust side region 40b of a predetermined thickness from the exhaust side surface 42b. The thickness of the exhaust side filter 42 (exhaust side region 40b) is, for example, 60% or more, 70% or more, and preferably 80% or more of the entire thickness of the filter 40. The thickness of the exhaust side filter 42 is, for example, 8.0 mm.

[0040] 5 and 6 is made of felt (nonwoven fabric) made of the chemical fiber polyester. The chemical fiber making up the intake side filter 41 is preferably, for example, polyester or polypropylene. The intake side filter 41 is made only of polyester fibers. The intake side filter 41 is a felt called needle felt, which is formed by needle punching to entangle the fibers with each other.

[0041] The intake side 41a of the intake side filter 41 shown in FIG. 5 is subjected to a heat treatment. The heat treatment temperature is, for example, a temperature near the melting point (250 to 260°C) of the polyester fiber, for example, 200 to 300°C. The heat treatment temperature is preferably the melting point of the polyester fiber or 250 to 270°C, which is slightly higher than the melting point. The polyester fiber forming the intake side 41a is pressed while melting by heating. This allows the intake side 41a to be finished smoothly. The intake side 41a has a smaller surface roughness than other areas of the intake side filter 41, and also has a smaller surface roughness than any area of ​​the exhaust side filter 42, for example, the exhaust side 42b.

[0042] The heat treatment and pressure treatment are performed on the entire intake side 41a. However, the polyester fibers are not melted over the entire intake side 41a. The polyester fibers forming the intake side 41a are melted into a fine mesh or scale shape on the intake side 41a. Therefore, the intake side 41a has gaps between the fibers through which outside air can pass. The intake side filter 41 with the surface treatment on the intake side 41a has slightly lower breathability than the intake side filter 41 without the surface treatment, but has almost the same breathability.

[0043] 5 and 6 is made of felt containing wool, which is an animal fiber. The proportion of wool contained in the exhaust filter 42 is, for example, 60%, 70%, and preferably 80% or more. In addition to wool, the exhaust filter 42 contains chemical fibers such as rayon. The exhaust filter 42 is a felt called a press felt, which is formed by compressing fibers with a press machine and entangling them with each other.

[0044] As shown in FIG. 6, an adhesive 43 for bonding the intake side filter 41 and the exhaust side filter 42 is provided between the exhaust side 41b of the intake side filter 41 and the intake side 42a of the exhaust side filter 42. The adhesive 43 is called hot melt and is mainly composed of a thermoplastic polymer that does not contain water or organic solvents. The adhesive 43 is arranged in a mesh-like shape on the exhaust side 41b or the intake side 42a. The adhesive 43 is formed, for example, in a sheet-like shape arranged in a mesh-like shape and is attached over substantially the entire surface of the exhaust side 41b of the intake side filter 41. The intake side 42a is bonded to the exhaust side 41b to which the adhesive 43 is attached, so that the intake side filter 41 and the exhaust side filter 42 are bonded to each other. The exhaust side 41b and the intake side 42a are bonded to each other in the mesh-like parts to which the adhesive 43 is attached, but breathability is ensured in the mesh-like gap parts to which the adhesive 43 is not attached. This allows outside air to flow from the exhaust side 41b to the intake side 42a (see FIG. 10).

[0045] The density of the intake side filter 41 (intake side region 40a) shown in Figures 5 and 6 is higher than the density of the exhaust side filter 42 (exhaust side region 40b). The density of the exhaust side filter 42 is, for example, 0.20 g / cm 3 More than 0.25g / cm 3 More than 0.70g / cm 3 Below 0.50g / cm 3 or less, preferably 0.25 to 0.35 g / cm 3 , more preferably 0.25 to 0.30 g / cm 3 It is.

[0046] 5, and 7 to 9, filter cover 33 is joined to the outside (left side) of intake side 41a of filter 40. Filter cover 33 has a disk shape with approximately the same diameter as filter 40. Filter cover 33 covers the entire intake side 41a of filter 40. A cylindrical insertion portion 33a through which motor shaft 25 is inserted is provided in the center of filter cover 33. Motor shaft 25 is inserted into the inner peripheral side of insertion portion 33a.

[0047] As shown in FIG. 6, an inner peripheral side pressing portion 33b is provided around the insertion portion 33a on the inner surface side of the filter cover 33. The inner peripheral side pressing portion 33b is formed in a ridge shape that protrudes inward (toward the filter 40) along the periphery of the insertion holes 41c, 41d of the intake side filter 41 and the periphery of the insertion holes 42c, 42d of the exhaust side filter 42. Similarly, an outer peripheral side pressing portion 33c is provided on the inner surface side of the filter cover 33 at the periphery of the filter cover 33. The outer peripheral side pressing portion 33c is formed in a ridge shape that protrudes inward along the periphery of the intake side filter 41 and the exhaust side filter 42. The inner peripheral side pressing portion 33b and the outer peripheral side pressing portion 33c are abutted against the inner peripheral edge and the outer peripheral edge of the outer surface of the intake side filter 41 and the exhaust side filter 42. This suppresses the filter 40 from being displaced in the filter accommodation recess 31b of the crankcase cover 31.

[0048] As shown in Figures 5, 6, 8 and 10, the filter cover 33 has multiple outer air intake holes 33d. The outer surface of the filter cover 33 has multiple annular wall portions 33e. Each annular wall portion 33e is formed in a cylindrical shape. An outer air intake hole 33d is provided on the inner periphery of each annular wall portion 33e, penetrating in the thickness direction. The depth of each outer air intake hole 33d is made larger than the hole diameter by the annular wall portion 33e. This reduces the intake noise.

[0049] As shown in Fig. 10, each annular wall portion 33e enters a recess 34d of the dust cover 34, which will be described later. As shown by the arrow W (intake path W), each annular wall portion 33e bends the intake path W from a direction along the surface direction of the filter cover 33 to a thickness direction (direction along the motor axis J). Each annular wall portion 33e forms a path bending portion that bends the intake path W of the outside air in the thickness direction. The outside air that has flowed into the outer surface side of the filter cover 33 flows into the outer intake hole 33d via a path bent in the thickness direction by the path bending portion. The outside air that has flowed into the outer intake hole 33d is blown against the intake side surface 41a of the intake side filter 41.

[0050] As shown in Fig. 5, insertion holes 33f are provided at four equal positions on the peripheral side of the filter cover 33, for inserting the small diameter portions of the screw boss portions 31f of the crankcase cover 31. As shown in Fig. 6, intermediate pressing portions 33g are provided on the inner surface side of the filter cover 33 around the insertion holes 33f. The intermediate pressing portions 33g are formed in a ridge shape that protrudes toward the filter 40, similar to the above-mentioned inner peripheral side pressing portions 33b and outer peripheral side pressing portions 33c. The intermediate pressing portions 33g press down the radial intermediate region of the filter 40.

[0051] 5 and 7, a positioning recess 33h is provided on the outer surface side of the filter cover 33 around the opening of each insertion hole 33f. Each positioning recess 33h is formed as a circular recess of a certain depth coaxially with the insertion hole 33f. A protrusion 34b of the dust cover 34 is inserted into each positioning recess 33h. This positions the dust cover 34 around the motor axis J with respect to the filter cover 33. An outer peripheral portion 33i of the filter cover 33 is bent toward the filter 40 at an angle of approximately 45° over the entire circumference with a certain width.

[0052] As shown in Figs. 5 and 6, a plurality of dust outlets 33j are provided in the outer peripheral portion 33i of the filter cover 33, penetrating the filter cover 33 in a generally radial direction. The dust outlets 33j are provided in pairs with an insertion hole 33f sandwiched therebetween in the circumferential direction. The filter cover 33 has four insertion holes 33f, so that the filter cover 33 has a total of eight dust outlets 33j. Two of the eight dust outlets 33j are located at the lower end of the filter cover 33 in a position extending in the vertical direction in which the filter cover 33 is attached to the crankcase cover 31. Dust repelled by the intake side filter 41 or dust peeled off from the intake side surface 41a of the intake side filter 41 is discharged to the outside of the filter cover 33 from one of the two dust outlets 33j located at the lower end of the filter cover 33 (see Fig. 7).

[0053] As shown in Figures 5 and 6, the dust cover 34 has a disk shape with approximately the same diameter as the filter cover 33. The flow of outside air generated by the intake fan 24 (see Figure 3) is blocked by the dust cover 34, preventing it from being blown directly onto the filter cover 33. This prevents dust and the like contained in the outside air from being blown directly onto the filter cover 33. A cylindrical insertion portion 34a is provided at the center of the inner surface of the dust cover 34. The insertion portion 34a protrudes toward the filter cover 33. The insertion portion 33a of the filter cover 33 is inserted into the insertion portion 34a. The tip of the motor shaft 25 protrudes outward through the inner periphery of the insertion portion 33a inserted into the insertion portion 34a. The intake fan 24 is supported on the protruding portion.

[0054] As shown in FIG. 10, the insertion portion 33a of the filter cover 33 is inserted (convex-concave engagement) into the insertion portion 34a of the dust cover 34, so that the filter cover 33 and the dust cover 34 are positioned coaxially with each other relative to the motor shaft 25.

[0055] 6 and 7, cylindrical protrusions 34b are provided on the inner surface of the dust cover 34 at four equal positions in the circumferential direction. Each of the protrusions 34b protrudes toward the filter cover 33. As described above, the four protrusions 34b are inserted into the positioning recesses 33h of the filter cover 33. This positions the dust cover 34 relative to the filter cover 33 in the direction of the motor axis J. In this positioned state, a gap is generated between the dust cover 34 and the filter cover 33 in the direction of the motor axis J. The gap between the dust cover 34 and the filter cover 33 in the direction of the motor axis J serves as an intake path W for introducing outside air into the crankcase 21.

[0056] As shown in Fig. 5, an insertion hole 34c through which a fixing screw 37 is inserted is provided at the center of each protrusion 34b. Circular recesses 34e are provided around the opening of each insertion hole 34c on the outer surface side of the dust cover 34. The four recesses 34e are recessed on the inner surface side, thereby providing protrusions 34b (see Fig. 6) protruding from the rear side.

[0057] 6 and 10, the inner surface of the dust cover 34 is provided with a number of recesses 34d corresponding to the annular wall portion 33e of the filter cover 33. Each recess 34d has a circular recessed shape with a diameter that allows the annular wall portion 33e to enter. Each recess 34d has a depth sufficient to allow the annular wall portion 33e to enter with a small gap. The gap between the bottom surface of each recess 34d and the annular wall portion 33e forms a part of the intake path W for drawing in outside air.

[0058] 10, each annular wall portion 33e of the filter cover 33 enters (overlaps in the direction of the motor axis J) into a recess 34d of the dust cover 34, thereby bending the intake path W at a substantially right angle, thereby forming an intake path W having a so-called labyrinth structure.

[0059] 7 to 10, outer periphery 34f of dust cover 34 is bent at an angle of approximately 45° toward filter cover 33 with a constant width over the entire circumference. Therefore, a constant gap is generated between outer periphery 34f of dust cover 34 and outer periphery 33i of filter cover 33. The gap between outer periphery 34f of dust cover 34 and outer periphery 33i of filter cover 33 serves as intake port 38 of intake path W.

[0060] As shown in Figs. 5 and 7, the dust cover 34 and the filter cover 33 are fastened together to the crankcase cover 31 by four fixing screws 37. The large diameter parts of the four screw bosses 31f of the crankcase cover 31 are located in the insertion holes 41e of the intake side filter 41 and the insertion holes 42e of the exhaust side filter 42. The small diameter parts of the screw bosses 31f are located straddling the insertion holes 33f of the filter cover 33 and the insertion holes 34c of the dust cover 34. The fixing screws 37 are fastened to the female thread parts 31h of the screw bosses 31f, so that the dust cover 34 and the filter cover 33 are fastened together to the crankcase cover 31. As a result, the filter 40 is held in the filter receiving recess 31b of the crankcase cover 31. The heads of the fixing screws 37 are located in the recesses 34e. As a result, the heads of the fixing screws 37 do not protrude from the outer surface of the dust cover 34.

[0061] 7, the electric motor 22 is started to rotate the intake fan 24, thereby blowing outside air onto the intake section 30. The blown outside air flows into the gap (intake port 38) between the dust cover 34 and the filter cover 33 through an intake port between the outer periphery 34f of the dust cover 34 and the outer periphery 33i of the filter cover 33, as shown by the arrow W in FIG. 10. The outer periphery 34f of the dust cover 34 and the outer periphery 33i of the filter cover 33 are bent in the same direction. Therefore, the intake path W of the intake section 30 is bent at the intake port 38.

[0062] As shown in Fig. 10, the outside air that has flowed in between the dust cover 34 and the filter cover 33 through the intake port 38 is blown against the annular wall portion 33e of the filter cover 33 and flows into the recessed portion 34d of the dust cover 34. At this stage, the flow of the outside air (intake path W) is bent at approximately a right angle. After being bent at two points in the intake path W, the outside air that has flowed into the recessed portion 34d flows into the outer intake hole 33d (the inner peripheral side of the annular wall portion 33e). The outside air that has flowed into the outer intake hole 33d is blown against the intake side surface 41a of the intake side filter 41.

[0063] As shown in FIG. 10, when the outside air is blown onto the intake side 41a, some of the dust contained in the outside air is repelled by the intake side filter 41, which has a high density, and falls, and is discharged from the dust outlet 33j (see FIGS. 5 and 7) to the outside of the filter cover 33. Some of the dust contained in the outside air may adhere to the intake side 41a, but it peels off from the intake side 41a, which has a small surface roughness, and falls, and is discharged from the dust outlet 33j to the outside of the filter cover 33. The dust is filtered out of the outside air that passes through the intake side filter 41. Furthermore, the outside air flows toward the right crankcase 21, and passes through the exhaust side 41b and the intake side 42a, which are bonded to each other, and enters the exhaust side filter 42. The dust is further filtered out of the outside air that passes through the exhaust side filter 42.

[0064] 10, clean outside air from which dust has been filtered by the intake-side filter 41 and the exhaust-side filter 42 flows into the crankcase 21 through the inner intake hole 31e of the crankcase cover 31. The outside air that has flowed in through the intake path W is supplied to the first compression section 11. The flowing-in outside air is supplied into the first cylinder 11a and compressed by the first piston 11b.

[0065] As described above, the intake side region 40a (intake side filter 41) of the filter 40 for the air compressor 1 shown in Figures 5 and 10 has a higher density than the exhaust side region 40b (exhaust side filter 42). This makes it possible to prevent dust from entering the intake side region 40a from the intake side surface 41a of the intake side region 40a. This makes it possible to prevent dust from accumulating in the intake side region 40a, and thus to prevent the filter 40 from becoming clogged.

[0066] 5 and 10, the surface roughness of the intake side 41a of the filter 40 for the air compressor 1 is smaller than the surface roughness of the exhaust side 42b. This makes it possible to prevent dust from accumulating on the intake side 41a. Even if dust adheres to the intake side 41a, the dust can be easily peeled off from the intake side 41a, which has a smaller surface roughness, by, for example, the wind blown toward the filter 40 by the intake fan 24 of the air compressor 1. This makes it possible to prevent clogging of the intake side 41a of the filter 40.

[0067] The intake side region 40a of the filter 40 for the air compressor 1 shown in Figs. 5 and 10 is made of felt made of chemical fiber. The exhaust side region 40b of the filter 40 is made of felt containing animal fiber. Therefore, the intake side region 40a is not easily altered by heating, pressurization, etc. Therefore, the intake side region 40a can be processed to suppress the accumulation of dust while maintaining the breathability of the intake side region 40a. On the other hand, the exhaust side region 40b is made of felt containing animal fiber, which is widely used in conventional intake filters for air compressors. Therefore, the exhaust side region 40b can be provided with the same breathability as conventional intake filters. Thus, the accumulation of dust in the intake side region 40a of the filter 40 can be suppressed while maintaining the breathability.

[0068] The chemical fibers in the intake side area 40a shown in Figures 5, 6, and 10 are made of polyester. Therefore, polyester chemical fibers are relatively inexpensive. Moreover, by processing the polyester chemical fibers by heating, pressing, etc., it is possible to improve the dust detachability. Therefore, clogging due to the accumulation of dust in the intake side area 40a can be suppressed.

[0069] The animal fiber of the exhaust side region 40b shown in Figures 5, 6, and 10 is wool. Therefore, the exhaust side region 40b is provided with wool felt, which can be processed with good dimensional accuracy. Therefore, it is possible to prevent the formation of a gap through which dust can enter between the housing portion of the filter 40 and the exhaust side region 40b. This can improve the filtering performance of the filter 40.

[0070] 5 and 10 has an intake side surface 41a that has been surface-treated to reduce the surface roughness. By reducing the surface roughness of the intake side surface 41a, the dust can be more easily removed from the intake side surface 41a.

[0071] The surface of the intake side region 40a shown in Figures 5 and 10 is heated and pressurized to form a surface-treated intake side 41a. Therefore, the surface roughness of the intake side 41a can be reduced by a simple surface treatment process of heating and pressing. As a result, the manufacturing cost of the filter 40 having the intake side 41a with high dust releasability can be reduced.

[0072] As shown in Figures 5, 6, and 10, the intake side region 40a is made of a different material than the exhaust side region 40b. The intake side region 40a is thinner than the exhaust side region 40b. Therefore, the thinner intake side region 40a can suppress the accumulation of dust, and the exhaust side region 40b, which occupies more than half of the filter 40, can ensure the same level of breathability as a conventional intake filter. This allows the filter 40 to be both anti-clogging and has good breathability.

[0073] 6, the intake side region 40a and the exhaust side region 40b are bonded to each other by a mesh-like adhesive 43. Therefore, the intake side region 40a and the exhaust side region 40b can be bonded to each other without impairing the breathability of the filter 40.

[0074] As shown in Figs. 5 to 7, the filter cover 33 covers the filter 40 from the intake side. The filter cover 33 has a dust outlet 33j that opens downward when the filter cover 33 is attached to the compression mechanism (compressor body) 10. Therefore, dust that has peeled off and fallen from the intake side region 40a of the filter 40 can be quickly discharged from the dust outlet 33j to the outside of the filter cover 33. Therefore, accumulation of dust inside the filter cover 33 can be suppressed.

[0075] As shown in Figs. 5 to 7, the filter cover 33 is attached to the compressor body 10 in a position in which it extends in the vertical direction. The filter cover 33 has a plurality of dust outlets 33j on its outer periphery. At least one of the plurality of dust outlets 33j opens downward. Therefore, the filter cover 33 has at least one dust outlet 33j that opens downward in any of a plurality of positions in which it extends in the vertical direction. Therefore, the filter cover 33 can be attached to the compressor body 10 without having to worry about the vertical orientation of the filter cover 33. This can improve the ease of assembly of the filter cover 33.

[0076] Various modifications can be made to the embodiment of the present disclosure described above. For example, in the present embodiment, the intake section 30 is provided on the left side of the compressor body 10, and the filter 40 is held in a position extending in the vertical direction. Instead of this, for example, the intake section 30 may be provided on the lower part of the compressor body 10, and the filter 40 may be held in a position extending in the approximately horizontal direction.

[0077] In this embodiment, the intake side filter 41 made of polyester chemical fiber is exemplified. The intake side filter 41 may be made of felt made of chemical fiber such as polypropylene, polyethylene, nylon, acrylic, aramid, rayon, etc. The intake side filter 41 may be made of multiple types of chemical fiber including polyester, for example.

[0078] In this embodiment, the intake side filter 41 has a higher density than the exhaust side filter 42. Instead of density, the intake side region 40a and the exhaust side region 40b may be compared in terms of the number of fibers per unit area when they are of the same thickness. In this case, the intake side region 40a has a larger number of fibers per unit area when they are of the same thickness than the exhaust side region 40b. Instead of density, air permeability, that is, kinetic viscosity per unit area ((cm 3 / sec) / cm 2 ) may be used to compare the intake side region 40a and the exhaust side region 40b. In this case, the exhaust side region 40b has higher breathability than the intake side region 40a.

[0079] In this embodiment, the exhaust filter 42 is made of felt containing wool, which is an animal fiber, and rayon, which is a chemical fiber. The exhaust filter 42 may be made of only animal fibers. The exhaust filter 42 may contain other animal fibers, such as camel hair, instead of wool. The exhaust filter 42 may contain, in addition to animal fibers, vegetable fibers, such as kenaf, cotton, or hemp, or chemical fibers other than rayon, such as polyester. The intake filter 41 may be made of multiple types of chemical fibers, including polyester. Although the exhaust filter 42 made of press felt is exemplified, the exhaust filter 42 may be provided, for example, with needle felt.

[0080] In the above embodiment, the intake side surface 41a is heated and pressurized to reduce the surface roughness of the intake side surface 41a. However, the intake side surface 41a may be alternatively surface-treated by heating only, by pressurizing only, chemical treatment, buffing, or the like.

[0081] In this embodiment, the adhesive 43 is applied to the exhaust side surface 41b of the intake side filter 41, and the intake side surface 42a is bonded to the exhaust side surface 41b. Alternatively, the adhesive 43 may be applied to the intake side surface 42a, and the exhaust side surface 41b may be bonded to the intake side surface 42a. [Explanation of symbols]

[0082] 1. Air compressor 2. Tank 3...legs 3a…Side protector 4…Base 5…Handle section 6...Main body cover, 6a...Ventilation hole 7...Discharge port (for high pressure) 7a…Adjustment dial 8...Discharge port (for low pressure) 8a…Adjustment dial 9...Operation unit 10...Compression mechanism (compressor body) 11...first compression section, 11a...first cylinder, 11b...first piston, 11c...first rod 11d...first compression chamber, 11e...auxiliary check valve 12... second compression section, 12a... second cylinder, 12b... second piston, 12c... second rod 12d…Second compression chamber 13...Supply pipe 14…First check valve 15…Air passage 21... crankcase, 21a... opening 22...electric motor, 22a...rotor, 22b...stator 23…Heat dissipation fan 24…Intake fan 25...motor shaft, 25a, 25b...bearings, 25c...regulating plate 26…First crank section 27…Second crank section 30…Intake section 31...Crankcase cover 31a...bearing recess, 31b...filter receiving recess, 31c...projection, 31d...insertion hole 31e: Inner air intake hole, 31f: Screw boss, 31g: Screw hole, 31h: Female screw 33: filter cover, 33a: insertion portion, 33b: inner peripheral pressing portion 33c... outer peripheral pressing portion, 33d... outer air intake hole, 33e... annular wall portion, 33f... insertion hole 33g: intermediate holding portion, 33h: positioning recess, 33i: outer periphery, 33j: dust exhaust port 34... dust cover, 34a... insertion portion, 34b... protrusion, 34c... insertion hole, 34d... recess 34e: recess, 34f: outer periphery 35…Mounting screw 36…Fixing screw 37…Fixing screw 38…Air intake 40...filter (intake filter), 40a...intake side area, 40b...exhaust side area 41... intake side filter, 41a... intake side, 41b... exhaust side 41c, 41d, 41e...Through holes 42...exhaust side filter, 42a...intake side, 42b...exhaust side 42c, 42d, 42e...Through holes 43...Glue J: Motor axis W…Intake path

Claims

1. An intake filter for an air compressor, comprising: An intake filter for air compressors in which the intake area is denser than the exhaust area.

2. An intake filter for an air compressor, comprising: An intake filter for air compressors, the surface roughness of the intake side being less than the surface roughness of the exhaust side.

3. An intake filter for an air compressor, comprising: The intake area is made of synthetic fiber felt. An intake filter for air compressors, the exhaust side area of ​​which is made of felt containing animal fibers.

4. 4. The air compressor intake filter according to claim 3, The synthetic fiber in the intake side region is made of polyester.

5. 5. The air compressor intake filter according to claim 3, 1. An intake filter for an air compressor, wherein the animal fiber in the exhaust side region is wool.

6. The air compressor intake filter according to any one of claims 1 to 3, An intake filter for an air compressor, the intake side region of which has an intake side surface that has been surface-treated to reduce surface roughness.

7. A method for producing the air compressor intake filter according to claim 6, comprising the steps of: A method for manufacturing an intake filter for an air compressor, comprising the steps of: heating and pressurizing the surface of the intake side region to form a surface-treated intake side surface.

8. The air compressor intake filter according to any one of claims 1 to 3, The intake side area is made of a different material than the exhaust side area. The intake filter for an air compressor has an intake side region thinner than an exhaust side region.

9. The air compressor intake filter according to any one of claims 1 to 3, An intake filter for an air compressor, in which an intake side region and an exhaust side region are bonded to each other by a mesh-like adhesive.

10. An air compressor equipped with the air compressor intake filter according to any one of claims 1 to 3, A filter cover is provided to cover the air compressor intake filter from the intake side, The filter cover of this air compressor has a dust exhaust port that opens downward when attached to the compressor body.

11. 11. The air compressor of claim 10, The filter cover is attached to the compressor body in a vertically extending position, The filter cover has a plurality of dust exhaust ports on an outer periphery, and at least one of the plurality of dust exhaust ports opens downward.

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