Air compressor

Abstract

To satisfy the necessity of enhancing maintenance performance by reducing the clogging of a filter of an outside air intake part, in an air compressor for supplying compressed air to an air tool of a nailing tool or the like as a power source.SOLUTION: A filter 32 is held between a crank case cover 31 of an intake part 30 and a filter cover 33. A dust prevention cover 34 is arranged at an outer face of the filter cover 33 so as to cover it. Ambient air is sucked into an outside intake hole 33d via an intake port 38 between an external peripheral part 33i of the filter cover 33 and an external peripheral part 34f of the dust prevention cover 34. The ambient air which is sucked via the outside intake port 33d of a labyrinth structure is blown to the filter 32. The ambient air whose dust is filtered by the filter 32 is sucked into a crane case 21 via an inside intake hole 31e.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present disclosure relates to an air compressor that supplies compressed air to air tools such as compressed air-powered nail guns and air dusters. [Background technology]

[0002] Patent Document 1 discloses technology related to an air compressor. The air compressor includes a reciprocating compression mechanism that generates compressed air. This compression mechanism generates compressed air by converting the rotational output of an electric motor into reciprocating motion of a piston in a cylinder using a crank mechanism. The compressed air generated by the compression mechanism is stored in a tank. The compressed air stored in the tank is supplied to an air tool.

[0003] Outside air to generate compressed air is drawn into a crankcase that houses a crank mechanism. For this reason, a noise-reducing and dust-proof filter is installed in the intake path of the outside air to the crankcase. According to Patent Document 1, the filter is attached to a crankcase cover that airtightly closes the end of the crankcase. Multiple intake holes provided in the crankcase cover are blocked by the filter. The dust-proof filter is held by a filter cover that is connected to the crankcase cover. Outside air is drawn into the intake holes through a gap between the periphery of the filter cover and the periphery of the crankcase cover. This deflects the intake path, reducing noise caused by the operating sound of the compression mechanism leaking to the outside. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5186799 Summary of the Invention [Problem to be solved by the invention]

[0005] In addition to noise control measures, air compressors also require increased dust protection within the crankcase. Taking dust protection measures, particularly for the intake path, improves the maintainability and durability of the air compressor. The present disclosure aims to further improve the dust protection of the intake path to the crankcase. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, an air compressor has, for example, a compression mechanism that generates compressed air by reciprocating a piston within a cylinder. The air compressor has, for example, a crankcase that houses the compression mechanism and an inner air intake port provided in the crankcase that allows outside air to be introduced into the crankcase. The air compressor has, for example, a filter that covers the inner air intake port from the outside, a filter cover that covers the filter from the outside and has an outer air intake port formed therein, and a dust cover that covers the filter cover from the outside. For example, the dust cover covers the outer air intake port of the filter cover, and a gap that introduces outside air is formed between the outer periphery of the dust cover and the filter cover.

[0007] Therefore, outside air flows into the outer air intake hole through the gap between the outer periphery of the dust cover and the filter cover. This bends the intake path of the outside air from the surface direction of the filter cover to the thickness direction, reducing the amount of dust mixed in the outside air that is blown directly onto the filter. This reduces clogging of the filter. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is an external perspective view of an air compressor. [Figure 2] This is a view taken along the arrow 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. [Figure 3] FIG. [Figure 4] FIG. 2 is a perspective view of the intake section according to the first embodiment. [Figure 5]FIG. 2 is an exploded perspective view of the intake section according to the first embodiment. [Figure 6] 6 is a cross-sectional view taken along line VI-VI in FIG. 5, and is a vertical cross-sectional view of the intake section according to the first embodiment. [Figure 7] 7 is a cross-sectional view taken along line VII-VII in FIG. 5, and is a vertical cross-sectional view of the intake section according to the first embodiment. [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 according to the first embodiment. [Figure 9] FIG. 8 is an enlarged view of part IX in FIG. [Figure 10] This is a perspective view of the crankcase cover, as seen from the outside. [Figure 11] 1 is a perspective view of a filter cover, as viewed from the inside. [Figure 12] 1 is a perspective view of a filter cover, showing the filter cover as viewed from the outer surface side. [Figure 13] This is a perspective view of the dust cover, as seen from the inside. [Figure 14] FIG. 10 is a perspective view of an intake section according to a second embodiment. [Figure 15] FIG. 10 is a vertical cross-sectional view of an intake section according to a second embodiment. [Figure 16] FIG. 10 is a perspective view of an intake section according to a third embodiment. [Figure 17] FIG. 10 is a vertical cross-sectional view of an intake section according to a third embodiment. [Figure 18] FIG. 10 is a perspective view of an intake section according to a fourth embodiment. [Figure 19] FIG. 10 is a vertical cross-sectional view of an intake section according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] In one or more embodiments, for example, the filter cover and the dust cover have a path bending portion that protrudes from at least one of them toward the other. This causes the air intake path that passes between the filter cover and the dust cover to bend in the thickness direction of the filter cover. This reduces the amount of dust mixed in the air that is blown directly onto the filter, and more reliably reduces clogging of the filter.

[0010] In one or more embodiments, for example, the path bending portion includes an annular wall portion that protrudes from the periphery of the outer air intake hole of the filter cover toward the dust cover, and a recess that is provided in the dust cover and into which the annular wall portion can enter, thereby ensuring that the air intake path is bent in the thickness direction of the filter cover.

[0011] In one or more embodiments, for example, the dust cover has an outer periphery that covers the outer periphery of the filter cover from the outside in the circumferential direction. As a result, for example, air passing between the outer periphery of the dust cover and the outer periphery of the filter cover flows from the filter cover to the dust cover. As a result, at the outer periphery of the protective cover, the air intake path is bent from the direction toward the protective cover to the surface direction of the filter cover.

[0012] In one or more embodiments, for example, the dust cover and the filter cover are connected to the crankcase by screwing together, which simplifies the structure for connecting the dust cover and the filter cover to the crankcase.

[0013] In one or more embodiments, for example, the dust cover has a recess formed in its outer surface that receives the head of the screw, thereby reducing or eliminating the amount of the head of the screw protruding from the outer surface of the dust cover.

[0014] In one or more embodiments, the compressor has an electric motor having a motor shaft that passes through a crankcase. For example, a filter cover and a dust cover each have a through-hole formed therein so that the motor shaft passes through. For example, the through-hole of the filter cover and the through-hole of the dust cover are fitted together with a recess, thereby positioning the filter cover and the dust cover coaxially with respect to the motor shaft. For example, a protrusion is provided on the back side of a recess in the dust cover so as to protrude toward the filter cover. For example, the protrusion is inserted into a positioning recess in the filter cover, thereby positioning the filter cover and the dust cover relative to each other around the motor shaft. This allows the filter cover and the dust cover to be positioned with respect to the motor shaft quickly and accurately, simplifying the assembly procedure of the compression mechanism.

[0015] In one or more embodiments, for example, a second filter is interposed between the filter cover and the dust cover, which further reliably reduces clogging of the filter and makes the compression mechanism quieter.

[0016] In one or more embodiments, the depth of the outer air intake holes is greater than the diameter of the outer air intake holes, which reduces sound leakage from the crankcase and reduces noise from the compression mechanism. [Example]

[0017] As shown in Figures 1 and 2, the air compressor 1 has two cylindrical tanks 2 that are long from front to back. The generated compressed air is stored in the two tanks 2. A total of four legs 3 are attached to the front and back of the two tanks 2. Each leg 3 is made of a rubber material with high vibration damping properties. Side protectors 3a are attached to each leg 3 side by side. A drain cock 2a for draining water is provided between the front parts of the two tanks 2. The tops of the two tanks 2 are connected to each other by a base 4. A compression mechanism 10 is mounted on the top surface of the base 4. Handles 5 for carrying are attached to the front and rear of the base 4, spanning the tops of the two tanks 2. Figure 1 shows the compression mechanism 10 covered by the main body cover 6.

[0018] On the front surface of the main body cover 6, two high-pressure outlets 7 and two low-pressure outlets 8 are arranged on the left and right sides. 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 are provided above the outlets 7 and 8, respectively, for setting the discharge pressure. An operating panel 9, mainly used for startup operations and including various display units, is provided on the front upper surface of the main body cover 6.

[0019] As shown in Figure 2, the compression mechanism 10 is exposed when the main body cover 6 is removed. As shown in Figures 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 4.

[0020] The electric motor 22 is a brushless motor capable of generating a relatively large starting torque. The electric motor 22 has a circular rotor 22a and a similarly circular stator 22b 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. 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 rotatably supported between the right and left sides of the crankcase 21 via a right-side bearing 25a and a left-side 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 .

[0021] 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 in communication with the outside air.

[0022] A first piston 11b is housed in the first cylinder 11a so as to be able to reciprocate back and forth. The first cylinder 11a extends forward from the front of the crankcase 21. The first piston 11b is connected to a first crank portion 26 of the motor shaft 25 via a first rod 11c.

[0023] A second piston 12b is housed in the second cylinder 12a so as to be able to reciprocate back and forth. The second cylinder 12a extends rearward from the rear 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.

[0024] 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 in one of the first compression section 11 and the second compression section 12 and an intake stroke in the other. During the 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 the 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.

[0025] The first compression chamber 11d of the first cylinder 11a and the second compression chamber 12d of the second cylinder 12a are connected to each other via a supply pipe 13. 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 through the auxiliary check valve 11e and into the supply pipe 13 is supplied directly to the second compression chamber 12d.

[0026] 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 of, for example, approximately 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.

[0027] An intake section 30 is provided on the left side of the crankcase 21. Outside air is introduced into the crankcase 21 through the intake section 30. Several embodiments of the intake section are illustrated below. Figures 2 to 8 show the intake section 30 of a first embodiment. Figures 4 to 8 show the details of the intake section 30. Figures 4 and 5 show the intake fan 24 removed from the motor shaft 25. In Figures 6 to 8, 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 outer side (outside), and the downstream side will also be referred to as the inner side (inside).

[0028] The intake section 30 of the first embodiment includes a crankcase cover 31 that airtightly seals the intake opening 21a of the crankcase 21, a filter 32 that seals the inner intake hole 31e of the crankcase cover 31, a filter cover 33 that covers the filter 32, and a dust cover 34 that covers the filter cover 33.

[0029] The opening 21a of the crankcase 21 is formed in a generally circular shape. As shown in Figures 5 and 9, 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 crankcase cover 31 airtightly seals the opening 21a. A cylindrical bearing recess 31a is provided in the center of the inner surface of the crankcase cover 31. The bearing 25b is held in the bearing recess 31a.

[0030] 8, one restricting 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 restricting plate 25c. By sandwiching the bearing 25b between the bottom of the bearing recess 31a and the restricting plate 25c, misalignment of the bearing 25b in the direction of the motor axis J is restricted.

[0031] As shown in Figures 5 to 8, a filter accommodating recess 31b that accommodates a filter 32 is provided on the outer surface of the crankcase cover 31. A cylindrical protrusion 31c is provided at the center of the filter accommodating recess 31b to form the bearing recess 31a on the inner surface. 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, into which fixing screws 36 that threadably fasten the restricting plate 25c are screwed. The filter accommodating recess 31b is provided around the protrusion 31c.

[0032] 5 to 7, a plurality of inner air intake holes 31e and a plurality of screw bosses 31f are provided on the bottom surface of the crankcase cover 31. In this embodiment, four screw bosses 31f are provided. An internal thread 31h is provided on the inner periphery of each screw boss 31f. As will be described later, fixing screws 37 are fastened to the internal threads 31h of the four screw bosses 31f, respectively, whereby the filter cover 33 and the dustproof cover 34 are screwed to the crankcase cover 31 by so-called co-fastening.

[0033] Each screw boss 31f is provided on the outer surface of the crankcase cover 31 so as to protrude 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. Inner air intake holes 31e are provided on both sides of each screw boss 31f. In this embodiment, a total of eight inner air intake holes 31e are provided. One filter 32 is housed in the filter housing recess 31b so as to block the eight inner air intake holes 31e from the outside.

[0034] The depth of the filter accommodating recess 31b is set to a depth that can accommodate the filter 32 in the thickness direction without excess or deficiency. Therefore, as shown in Figures 6 to 8, the outer peripheral end face of the crankcase cover 31 and the outer surface of the filter 32 are substantially flush with each other.

[0035] The filter 32 is a sound-deadening and dust-proof filter made of felt, and is generally disk-shaped. The filter 32 has a through-hole 32a at its center, through which the protrusion 31c of the crankcase cover 31 is inserted. Four through-holes 32b are provided at equal quarter-circumference positions around the insertion hole 32a, through which the screw holes 31g of the crankcase cover 31 are inserted. Four through-holes 32c are provided around the insertion hole 32a, through which the large-diameter portions of the screw bosses 31f of the crankcase cover 31 are inserted.

[0036] A filter cover 33 is attached to the outer surface of the filter 32. The filter cover 33 has a disk shape with approximately the same diameter as the filter 32. The filter cover 33 covers the entire outer surface of the filter 32. A cylindrical insertion portion 33a through which the motor shaft 25 is inserted is provided in the center of the filter cover 33. The motor shaft 25 is inserted into the inner periphery of the insertion portion 33a.

[0037] As shown in FIG. 11 , an inner peripheral pressing portion 33b is provided on the inner surface of the filter cover 33 around the insertion portion 33a. The inner peripheral pressing portion 33b is formed in a ridge shape that protrudes inward (toward the filter 32) along the periphery of the insertion holes 32a, 32b of the filter 32. Similarly, an outer peripheral pressing portion 33c is provided on the inner surface of the filter cover 33 at the periphery of the filter cover 33. The outer peripheral pressing portion 33c is formed in a ridge shape that protrudes inward along the periphery of the filter 32. The inner peripheral pressing portion 33b and the outer peripheral pressing portion 33c abut against the inner periphery and outer periphery of the outer surface of the filter 32. This prevents the filter 32 from shifting position within the filter accommodating recess 31b of the crankcase cover 31.

[0038] The filter cover 33 has multiple outer air intake holes 33d. As shown in Figures 5, 7, 9, and 12, 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. The inner periphery of each annular wall portion 33e forms an outer air intake hole 33d that penetrates in the thickness direction. The depth of each outer air intake hole 33d is made larger than the hole diameter by the annular wall portions 33e. This reduces intake noise.

[0039] Each annular wall portion 33e extends into a recess 34d of the dust cover 34, which will be described later. As shown by arrow W (intake path W) in Figure 9, each annular wall portion 33e bends the intake path W from a direction along the surface of the filter cover 33 to a thickness direction (a direction along the motor axis J). Each annular wall portion 33e forms a path bending portion that bends the intake path W of outside air in the thickness direction. Outside air that has flowed into the outer surface side of the filter cover 33 flows through a path bent in the thickness direction by the path bending portion and into the outer air intake hole 33d. The outside air that has flowed into the outer air intake hole 33d is blown toward the filter 32.

[0040] Insertion holes 33f are provided at four equal positions on the peripheral edge 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 Figure 11, intermediate pressing portions 33g are provided on the inner surface of the filter cover 33 around the insertion holes 33f. Like the inner peripheral pressing portions 33b and the outer peripheral pressing portions 33c, the intermediate pressing portions 33g are formed in a ridge shape that protrudes toward the filter 32. The intermediate pressing portions 33g press down on the radially intermediate regions of the filter 32.

[0041] 5 and 10, positioning recesses 33h are provided on the outer surface 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 and coaxial with the insertion hole 33f. The protrusions 34b of the dust cover 34 are inserted into each positioning recess 33h. This positions the dust cover 34 around the motor axis J relative to the filter cover 33.

[0042] The outer peripheral portion 33i of the filter cover 33 is bent toward the filter 32 at an angle of approximately 45° over the entire circumference with a constant width.

[0043] As shown in Figure 13, the dust cover 34 has a disk shape with approximately the same diameter as the filter cover 33. The dust cover 34 blocks the flow of outside air generated by the intake fan 24, preventing it from being blown directly onto the filter cover 33. This prevents dust and other particles 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.

[0044] As shown in FIGS. 6 to 9, the insertion portion 33a of the filter cover 33 is inserted (convex-concave fit) 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 respect to the motor shaft 25.

[0045] Cylindrical protrusions 34b are provided on the inner surface of the dustproof 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 dustproof 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 dustproof cover 34 and the filter cover 33 in the direction of the motor axis J. The gap between the dustproof 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.

[0046] An insertion hole 34c is provided at the center of each protrusion 34b, through which a fixing screw 37 is inserted. As shown in Fig. 5, a circular recess 34e is 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 protruding on the back side.

[0047] The inner surface of the dust cover 34 is provided with a number of recesses 34d corresponding to the annular wall 33e of the filter cover 33. Each recess 34d has a circular recessed shape with a diameter that allows the annular wall 33e to enter. Each recess 34d has a depth sufficient to allow the annular wall 33e to enter with a small gap. The gap between the bottom surface of each recess 34d and the annular wall 33e forms part of the intake path W for drawing in outside air.

[0048] Each annular wall portion 33e of the filter cover 33 enters (overlaps in the direction of the motor axis J) the recessed portion 34d of the dust cover 34, thereby bending the intake path W at a substantially right angle, thereby forming an intake path W with a so-called labyrinth structure.

[0049] The outer periphery 34f of the dust cover 34 is bent at an angle of approximately 45° over the entire circumference with a constant width toward the filter cover 33. Therefore, as shown in Figures 6 to 9, a constant gap is generated between the outer periphery 34f of the dust cover 34 and the outer periphery 33i of the filter cover 33. The gap between the outer periphery 34f of the dust cover 34 and the outer periphery 33i of the filter cover 33 serves as an intake port 38 of the intake path W.

[0050] As shown in Figures 5 and 6, the dustproof cover 34 and the filter cover 33 are fastened to the crankcase cover 31 by four fixing screws 37. The large-diameter portions of the four screw bosses 31f of the crankcase cover 31 are positioned within the insertion holes 32c of the filter 32. The small-diameter portions of the screw bosses 31f are positioned straddling the insertion holes 33f of the filter cover 33 and the insertion holes 34c of the dustproof cover 34. The dustproof cover 34 and the filter cover 33 are fastened together to the crankcase cover 31 by fastening the fixing screws 37 into the female thread portions 31h of each screw boss 31f. This holds the filter 32 in the filter receiving recess 31b of the crankcase cover 31. The head of each fixing screw 37 is positioned within the recess 34e. This prevents the heads of the fixing screws 37 from protruding from the outer surface of the dustproof cover 34.

[0051] When the electric motor 22 is started, the intake fan 24 rotates, causing outside air to be blown onto the intake section 30. The blown outside air flows into the gap (intake port 38) between the dustproof cover 34 and the filter cover 33 through an intake port between the outer periphery 34f of the dustproof cover 34 and the outer periphery 33i of the filter cover 33, as shown by the arrow W in Figure 9. The outer periphery 34f of the dustproof 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.

[0052] The outside air that flows into the gap between the dust cover 34 and the filter cover 33 through the air 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 flows into the recessed portion 34d flows into the outer air intake hole 33d (the inner peripheral side of the annular wall portion 33e). The outside air that flows into the outer air intake hole 33d is blown against the filter 32.

[0053] The outside air passes through the filter 32, filtering out dust. The clean outside air from which the dust has been filtered by the filter 32 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.

[0054] According to the air compressor 1 of the first embodiment described above, outside air flows into the outer air intake holes 33d through the air intake port 38 between the outer peripheral portion 34f of the dust cover 34 and the filter cover 33. As a result, the air intake path W of the outside air is bent from the surface direction of the filter cover 33 to the thickness direction (the direction of the motor axis J), which reduces the amount of dust mixed in the outside air being blown directly onto the filter 32. This reduces clogging of the filter 32.

[0055] According to the first embodiment, a path bending portion (annular wall portion 33e) is provided between the filter cover 33 and the dustproof cover 34. As a result, the intake path W of the outside air passing between the filter cover 33 and the dustproof cover 34 is bent in the thickness direction (direction of the motor axis J) of the filter cover 33. This reduces the amount of dust mixed in the outside air that is blown directly onto the filter 32, and more reliably reduces clogging of the filter 32.

[0056] According to the first embodiment, the path bending portion includes an annular wall portion 33e that protrudes from the periphery of the outer air intake hole 33d of the filter cover 33 toward the dust cover 34, and a recess 34d that is provided on the dust cover 34 and into which the annular wall portion 33e can enter. This ensures that the air intake path W is bent in the thickness direction of the filter cover 33.

[0057] According to the first embodiment, the dustproof cover 34 and the filter cover 33 are joined to the crankcase cover 31 by co-tightening the fixing screws 37. This simplifies the joining structure of the dustproof cover 34 and the filter cover 33 to the crankcase cover 31 and ultimately to the crankcase 21.

[0058] According to the first embodiment, the outer surface of the dustproof cover 34 is provided with a recess 34e for receiving the head of the fixing screw 37. A protrusion 34b is provided on the back side (inner surface) of the recess 34e. The protrusion 34b is inserted into the positioning recess 33h of the filter cover 33. This positions the dustproof cover 34 relative to the filter cover 33 around the motor axis J. The engagement structure of the protrusion 34b with the positioning recess 33h determines the position of the dustproof cover 34 relative to the filter cover 33. This improves the ease of assembly of the dustproof cover 34.

[0059] According to the first embodiment, the insertion portion 33a of the filter cover 33 is inserted into the insertion portion 34a of the dustproof cover 34, and the filter cover 33 and the dustproof cover 34 are positioned coaxially with respect to the motor shaft 25. The configuration may be changed so that the insertion portion of the dustproof cover is inserted into the inner peripheral side of the insertion portion of the filter cover.

[0060] According to the first embodiment, the annular wall portion 33e is provided around the outer air intake hole 33d, so that the depth of the outer air intake hole 33d is greater than the diameter of the hole, thereby suppressing sound leakage from inside the crankcase 21 and reducing noise generated by the compression mechanism 10.

[0061] Various modifications can be made to the above-described embodiments. For example, in the first embodiment, the annular wall portion 33e of the filter cover 33 and the recessed portion 34d of the dust cover 34 are provided as the path bending portion, but the recessed portion 34d of the dust cover 34 may be omitted.

[0062] Furthermore, although an example of a configuration in which an annular wall portion 33e is provided around the outer air intake hole 33d of the filter cover 33 has been given, instead of the annular wall portion 33e of the filter cover 33, for example, an annular or flat curved wall portion may be provided on the inner surface of the dust cover 34, protruding toward the outer air intake hole 33d, to form a path bend.

[0063] The angle of inclination of the outer peripheral portion 33i of the filter cover 33 and the outer peripheral portion 34f of the dust cover 34 can be changed. In addition, one or both of the inclined outer peripheral portions 33i and 34f may be omitted.

[0064] 14 and 15 show an intake section 40 according to the second embodiment. Since the basic configuration of the air compressor 1, excluding the intake section 40, does not require any changes, the same reference numerals are used and their description will be omitted. Furthermore, for the intake section 40, the same members and configuration as those of the first embodiment are used and their description will be omitted.

[0065] In the second embodiment, the dustproof cover 42 is different from that in the first embodiment. The dustproof cover 42 has a larger diameter than the dustproof cover 34 of the first embodiment. The outer periphery 42a of the dustproof cover 42 is bent by approximately 90 degrees toward the crankcase 21. As a result, the outer periphery of the filter cover 41 and the crankcase cover 31 are covered from the sides by the outer periphery 42a of the dustproof cover 42.

[0066] As shown in Fig. 14, the outer peripheral portion 42a bent toward the crankcase 21 is provided in a range excluding an area approximately 90 degrees below the motor axis J. Therefore, as shown in Fig. 15, in an area approximately 90 degrees below the intake portion 40, the peripheries of the filter cover 41 and the crankcase cover 31 are open downward.

[0067] In the second embodiment, a number of thick portions 42b are provided on the outer surface of the dust cover 42. The thick portions 42b are provided corresponding to the recesses 34d on the inner surface side (see FIG. 13). The thick portions 42b increase the thickness of the bottom of the recesses 34d. This makes the recesses 34d deeper, and the annular wall portion 41a of the filter cover 41 is formed with a longer protrusion length than the annular wall portion 33e of the first embodiment. The inner peripheral hole of the annular wall portion 33e becomes the outer intake hole 33d that penetrates to the inner surface side. By forming the annular wall portion 41a longer, dust in the intake outside air is more reliably separated at the bent path portion. Furthermore, by forming the outer intake hole 33d deeper, the intake section 40 is made quieter.

[0068] In the second embodiment, in addition to the curved path portion formed by the annular wall portion 41a of the filter cover 41 and the recess 34d of the dust cover 42, curved path portions with a labyrinth structure formed by locally narrowing the gap between the filter cover 41 and the dust cover 42 are provided in multiple locations.

[0069] 14, screw cover portions 42c that cover the heads of a total of six mounting screws 35 are provided on the outer peripheral portion 42a of the dust cover 42. The outer peripheral portion 42a is provided along a range of approximately 270° around the motor axis J to cover the heads of the mounting screws 35.

[0070] According to the second embodiment, the outer periphery 42a of the dust cover 42 covers the outer peripheries of the filter cover 41 and the crankcase cover 31 from the sides. Therefore, when outside air flows through the intake port 43 between the outer periphery 42a of the dust cover 42 and the outer periphery of the filter cover 41, it flows in a direction from the filter cover 41 toward the dust cover 42 (the opposite direction to the inflow direction of the outer air intake holes 33d). As a result, the intake path W of the outside air is bent from the direction toward the protection cover 42 toward the surface of the filter cover 41. In the second embodiment, the outer periphery 42a of the dust cover 42 bends the intake path W more reliably than the intake port 38 of the first embodiment.

[0071] 16 and 17 show the intake section 50 of the third embodiment. Components and configurations that do not require modification are assigned the same reference numerals and their description will be omitted. The third embodiment has a configuration in which a second filter 53 is added to the configuration of the second embodiment. The second filter 53 has a circular ring shape that follows the periphery of the filter cover 51. The second filter 53 is formed from the same felt material as the filter 32.

[0072] As shown in Fig. 17, a flat base portion 51a is provided around the entire outer peripheral edge of the filter cover 51. The second filter 53 is held by being sandwiched between the base portion 51a and the inner surface of the dust cover 52. As in the second embodiment, an outer peripheral portion 52a is provided around the outer periphery of the dust cover 52 so as to cover the sides of the peripheral edges of the filter cover 51 and the crankcase cover 31. In the third embodiment, the outer peripheral portion 52a is provided around the entire periphery of the dust cover 52. As in the second embodiment, the outer peripheral portion 52a is provided with screw cover portions 52b that cover the heads of the mounting screws 35.

[0073] Outside air is taken in through an air intake 54 between an outer periphery 52a of the dust cover 52 and the peripheral edge of the filter cover 51. A second filter 53 is disposed along the entire periphery of the air intake 54 which serves as the air intake.

[0074] According to the third embodiment, the second filter 53 is interposed between the filter cover 51 and the dust cover 52. This further reduces clogging of the filter 32. In addition, the intake section 50 and, ultimately, the compression mechanism 10 are made even quieter.

[0075] 18 and 19 show an intake section 60 according to the reference technology. The intake section 60 has a configuration in which the dustproof cover 34 is removed from the intake section 30 of the first embodiment. As a result, the outer surface of the filter cover 61 is exposed. As in the first embodiment, a number of cylindrical annular wall portions 61a are provided on the outer surface of the filter cover 61. On the inner periphery of each annular wall portion 61a, outer intake holes 61b are provided that penetrate to the inner surface.

[0076] In the intake section 60, a recess 61c that accommodates the head of the fixing screw 37 is shallower than the positioning recess 33h of the first embodiment.

[0077] According to the intake unit 60 of the related art, rotation of the intake fan 24 causes outside air to be blown onto the entire outer surface of the filter cover 61. The direction in which the outside air is blown is substantially along the motor axis J. Therefore, although some of the outside air flows directly into the outer air intake holes 61b, most of the remaining outside air is blown onto the outer surface of the filter cover 61.

[0078] The outside air blown onto the outer surface of the filter cover 61 flows along the outer surface and then blows against the annular wall portion 61a, bending the intake path. This bent path removes dust from the outside air. The clean outside air from which the dust has been removed flows into the outer air intake holes 61b.

[0079] Even when the filter cover 61 is exposed in this way, a curved path can be formed by providing the annular wall 61a around the outer air intake hole 61b, which makes it possible to efficiently remove dust from the outside air and reduce clogging of the filter 32.

[0080] The air compressor 1 of the first to third embodiments is an example of an air compressor according to an aspect of the present disclosure. The compression mechanism 10 of the first to third embodiments is an example of a compression mechanism according to an aspect of the present disclosure. The crankcase 21 of the first to third embodiments is an example of a crankcase according to an aspect of the present disclosure. The inner air intake hole 31e of the first to third embodiments is an example of an inner air intake hole according to an aspect of the present disclosure.

[0081] Filter 32 in the first to third embodiments is an example of a filter in one aspect of the present disclosure. Filter cover 33 in the first embodiment, filter cover 41 in the second embodiment, and filter cover 51 in the third embodiment are examples of a filter cover in one aspect of the present disclosure. Outer air intake hole 33d in the first embodiment and outer air intake hole 33d in the second embodiment are examples of outer air intake holes in one aspect of the present disclosure.

[0082] The dust cover 34 of the first embodiment, the dust cover 42 of the second embodiment, and the dust cover 52 of the third embodiment are examples of dust covers in one aspect of the present disclosure. The outer peripheral portion 34f of the first embodiment, the outer peripheral portion 42a of the second embodiment, and the outer peripheral portion 52a of the third embodiment are examples of outer peripheral portions in one aspect of the present disclosure. The air intake 38 of the first embodiment, the air intake 43 of the second embodiment, and the air intake 54 of the third embodiment are examples of gaps in one aspect of the present disclosure. [Explanation of symbols]

[0083] 1...Air compressor 2. Tank 3...legs 3a...Side protector 4...Base 5...Handle 6...Main unit cover 7...Discharge port (for high pressure) 7a...Adjustment dial 8...Discharge port (for low pressure) 8a...Adjustment dial 9...Operation unit 10...Compression mechanism 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... restricting plate 26...First crank section 27...Second crank section 30... Intake section (first embodiment) W...Intake path 31...Crankcase cover 31a...bearing recess, 31b...filter accommodating recess, 31c...projection, 31d...insertion hole 31e...Inner air intake hole, 31f...Thread boss portion, 31g...Thread hole, 31h...Internal thread portion 32...Filter 32a, 32b, 32c...Through holes 33...Filter cover 33a...insertion portion, 33b...inner circumference side pressing portion, 33c...outer circumference side pressing portion 33d...outer intake hole, 33e...annular wall portion, 33f...through hole, 33g...intermediate holding portion 33h: Positioning recess, 33i: Outer periphery 34...Dustproof 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... Intake section (second embodiment) 41...Filter cover 41a...Annular wall portion 42...Dustproof cover 42a...outer periphery, 42b...thick wall portion, 42c...screw cover portion 43...Air intake 50...intake section (third embodiment) 51...Filter cover 51a...Base 52...Dustproof cover 52a...outer periphery, 52b...screw cover 53...Second filter 54...Air intake 60...Intake section (reference technology) 61...Filter cover 61a...annular wall portion, 61b...outer air intake hole, 61c...recess

Claims

1. An air compressor, a compression mechanism that generates compressed air by reciprocating a piston within a cylinder; a crankcase that houses the compression mechanism; an inner air intake hole provided in the crankcase to allow outside air to be introduced into the crankcase; and a filter covering the inner air intake hole from the outside. a filter cover that covers the filter from the outside and has an outer air intake hole formed therein; a dustproof cover that covers the filter cover from the outside, the dustproof cover covers the outer air intake hole of the filter cover, and a gap for introducing outside air is formed between the outer periphery of the dustproof cover and the filter cover; a path bending portion protruding from at least one of the filter cover and the dustproof cover toward the other so as to bend an intake path of air passing between the filter cover and the dustproof cover in a thickness direction of the filter cover, The path bending portion includes an annular wall portion that protrudes from around the outer air intake hole of the filter cover toward the dustproof cover, and a recess provided in the dustproof cover into which the annular wall portion can enter.

2. 2. The air compressor of claim 1, The dustproof cover has an outer peripheral portion that covers the outer peripheral portion of the filter cover from the outside in the circumferential direction, and air passing between the outer peripheral portion of the dustproof cover and the outer peripheral portion of the filter cover flows from the filter cover toward the dustproof cover.

3. 3. The air compressor according to claim 1 or 2, The air compressor has the dust cover and the filter cover joined to the crankcase by screwing them together.

4. 4. The air compressor according to claim 3, The dustproof cover has a recess formed on its outer surface to accommodate the head of the screw.

5. 5. The air compressor according to claim 4, an electric motor having a motor shaft passing through the crankcase; an insertion portion is formed in each of the filter cover and the dustproof cover so that the motor shaft passes through; The insertion portion of the filter cover and the insertion portion of the dustproof cover are fitted to each other with a concave-convex shape, so that the filter cover and the dustproof cover are positioned coaxially with respect to the motor shaft, A convex portion is provided on the back side of the recess of the dustproof cover so as to protrude toward the filter cover, The convex portion is inserted into the positioning recess of the filter cover, and the filter cover and the dustproof cover are positioned relative to each other around the motor shaft.

6. The air compressor according to any one of claims 1 to 5, An air compressor having a second filter interposed between the filter cover and the dustproof cover.

7. The air compressor according to any one of claims 1 to 6, An air compressor in which the depth of the outer air intake hole is greater than the diameter of the outer air intake hole.

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