Gear pump and gear pump type coating device equipped with the same

Abstract

To provide a gear pump in which wear is hardly generated in a portion opposing a gear in a housing, and a gear pump type coating device.SOLUTION: A gear pump 1 comprises a pair of gears 3 which are engaged with each other, a pair of rotating shafts 41, 42 protruding from end faces of a pair of the gears 3, and a housing 2 for rotatably supporting a pair of the gears 3 via a pair of the rotating shafts 41, 42. The housing 2 has support plates 23, 24 for supporting a pair of the rotating shafts 41, 42. The support plate 23 includes a plate main body 231 including a fixing hole for fitment to the other adjacent member, and an opening part formed at a portion opposing the end faces of a pair of the gears 3, and a gear opposing part 232 fit into the opening part, supporting a pair of the rotating shafts 41, 42, and opposing the end faces of the pair of the gears 3. The gear opposing part 232 is harder than the plate main body 231.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a gear pump and a gear pump type coating device equipped with the same. [Background technology]

[0002] Patent Document 1 discloses a conventional gear pump. The gear pump described in Patent Document 1 includes a cover frame having a gear chamber and a pair of gears rotatably supported within the gear chamber. The rotation shafts of the gears are supported by the cover frame (housing).

[0003] In a gear pump, when a pair of gears rotates, fluid is supplied from an inlet port of a cover frame, and fluid in a gear chamber is pumped out from an outlet port. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Application Publication No. 2-54393 Summary of the Invention [Problem to be solved by the invention]

[0005] In this type of gear pump, a highly viscous fluid gets into the gap between the end face of the gear and the portion of the inner surface of the cover frame that faces the end face of the gear. As a result, the gear pump described in Patent Document 1 has a problem in that the portion of the inner surface of the cover frame that faces the end face of the gear is prone to wear as the gear rotates.

[0006] The present invention has been made in view of the above circumstances, and has as its object to provide a gear pump in which wear is less likely to occur in the portion facing the gear inside the housing, and a gear pump type coating device equipped with the same. [Means for solving the problem]

[0007] A gear pump according to one aspect of the present invention includes a pair of gears that mesh with each other, a pair of rotary shafts that protrude from end faces of the pair of gears, and a housing that rotatably supports the pair of gears via the pair of rotary shafts and has an outlet port through which fluid pumped by the pair of gears is discharged. The housing has a support plate that supports the pair of rotary shafts. The support plate includes a plate main body that includes fixing holes for fixing to an adjacent member and openings formed in portions facing the end faces of the pair of gears, and gear opposing portions that are fitted into the openings to support the pair of rotary shafts and face the end faces of the pair of gears. The gear opposing portions are harder than the plate main body.

[0008] A gear pump coating device according to one aspect of the present invention includes the above-described gear pump and a drive unit that drives one of the pair of gears in the gear pump. [Effects of the Invention]

[0009] The gear pump according to the above aspect of the present invention and the gear pump type coating device equipped with the same have the advantage that wear is less likely to occur in the portion of the housing facing the gear. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a side view of a gear pump type coating device according to an embodiment. [Figure 2] 1 is a front view of a gear pump type coating device according to an embodiment. [Figure 3] FIG. 1 is a perspective view of a gear pump according to an embodiment. [Figure 4] FIG. 1 is a side view of a gear pump according to an embodiment. [Figure 5] FIG. 1 is an exploded perspective view of a gear pump according to an embodiment. [Figure 6] FIG. 2 is a front view of a casing body and a gear according to the embodiment. [Figure 7]1A is a front view of a first plate (support plate) according to the embodiment, and FIG. 1B is a front view of a second plate (support plate) according to the embodiment. [Figure 8] FIG. 5 is a cross-sectional view taken along line AA in FIG. 4. [Figure 9] 1A is a perspective view of the discharge plate according to the embodiment as seen from behind, and FIG. 1B is a front view of the discharge plate according to the embodiment. [Figure 10] FIG. 9 is a cross-sectional perspective view taken along line BB in FIG. 8. DETAILED DESCRIPTION OF THE INVENTION

[0011] <Embodiment> The gear pump type coating device 100 according to this embodiment is a device for coating an object with a fluid. The gear pump type coating device 100 can be attached to, for example, a robot arm and used for coating on a production line.

[0012] Fluids that can be used with the gear pump type coating apparatus 100 include, for example, adhesives, sealants, coating agents, sealants, and paints. The gear pump type coating apparatus 100 according to this embodiment can be used with highly viscous fluids. Here, "high viscosity" means a viscosity of 50 Pa·S or higher. However, the gear pump type coating apparatus 100 can also be used with fluids other than high viscosity fluids, and can be used with any fluid having a viscosity of 0.01 Pa·S or higher and 2000 Pa·S or lower.

[0013] The term "painting" as used herein means applying a fluid to an object. There are no particular limitations on the manner of "painting," and examples include painting, spray coating, and the like.

[0014] For ease of explanation, the discharge direction of the gear pump type coating apparatus 100 in the longitudinal direction of the gear pump 1 will be defined as the "forward direction," and the opposite direction will be defined as the "rearward direction." Furthermore, a direction parallel to the forward and rearward directions will be defined as the "front-rear direction," a direction perpendicular to the front-rear direction and in which the fluid supply unit 6 protrudes will be defined as the "upward direction," and the opposite direction will be defined as the "downward direction." Furthermore, as shown in FIG. 2, the "leftward direction" and "rightward direction" are defined based on the view of the pump type coating apparatus 100 from the front to the rear. However, these definitions are provided merely for ease of explanation and are not intended to specify the manner of use of the gear pump type coating apparatus 100.

[0015] As shown in FIG. 1, the gear pump type coating device 100 includes a gear pump 1, a drive unit 5 that drives the gear pump 1, a fluid supply unit 6 that supplies fluid to the gear pump 1, and a fluid discharge unit 7 that discharges the fluid sent from the gear pump 1.

[0016] (Gear pump 1) Gear pump 1 is a device for pumping fluid. Gear pump 1 can continuously pump fluid with high metering accuracy without generating pulsation like a positive displacement reciprocating pump. As shown in FIG. 3, gear pump 1 includes housing 2 having gear chamber 21, a pair of gears 3 housed in gear chamber 21, and a pair of rotary shafts 41, 42. As shown in FIG. 4, gear pump 1 has one rotary shaft 41 protruding rearward from the rear end face of housing 2. Rotation of rotary shaft 41 allows for suction through supply port 225 and discharge through discharge port 262.

[0017] The gear pump 1 according to this embodiment is an external gear pump. Here, the gear pump 1 will be described as using a spur gear as the gear 3, but the present invention is not limited to gear pumps using spur gears, and may also be gear pumps using, for example, helical gears, double helical gears, etc.

[0018] (Housing 2) As shown in FIG. 3, the housing 2 is the casing of the gear pump 1. As described above, the housing 2 has the gear chamber 21. The gear chamber 21 is a chamber that houses the pair of gears 3. The housing 2 rotatably supports the gears 3 within the gear chamber 21 via rotation shafts 41 and 42. As the pair of gears 3 rotate, the fluid within the gear chamber 21 is pressurized, and the fluid is sent out from the gear chamber 21. That is, as the pair of gears 3 rotate, the housing 2 discharges the fluid from the discharge port 262 (FIG. 4).

[0019] 6, the portion where the pair of gears 3 mesh together may be referred to as a "meshing portion 31." In addition, in the gear chamber 21, the space to which the fluid is supplied and which faces the tooth surfaces of the gears 3 is referred to as a "suction space 211," and the space in the gear chamber 21 to which the fluid is discharged and which faces the tooth surfaces of the gears 3 is referred to as a "discharge space 212."

[0020] 5, the housing 2 includes a housing main body 22, a pair of support plates 23 and 24, a back plate 25, and a discharge plate 26. The housing 2 is configured by assembling the housing main body 22, the pair of support plates 23 and 24, the back plate 25, and the discharge plate 26 with fasteners such as bolts.

[0021] (Housing body 22) The housing main body 22 is a part that constitutes the main body of the housing 2. As shown in Fig. 6, the housing main body 22 includes a main body portion 221 and a protrusion portion 222 that protrudes upward from the main body portion 221. The main body portion 221 and the protrusion portion 222 are integrally formed.

[0022] The main body portion 221 is a portion that overlaps with the support plates 23 and 24, the back plate 25, and the discharge plate 26 when the housing main body 22 is viewed in the front-to-rear direction. The main body portion 221 has a gear accommodating opening 223 in which a pair of gears 3 are accommodated. The gear accommodating opening 223 is a portion that forms part of the gear chamber 21. The gear accommodating opening 223 penetrates the housing main body 22 from the front to the rear. The inner circumferential surface of the gear accommodating opening 223 closely faces the outer circumferential surface (tooth tips) of the gear 3. As a result, the fluid accommodated in the space surrounded by adjacent teeth of the gear 3 and the inner circumferential surface of the gear accommodating opening 223 is sent to the discharge space 212 as the gear 3 rotates. Here, "closely faces" means that the inner circumferential surface of the gear accommodating opening 223 and the tooth tips of the gear 3 are close enough to each other so that the fluid can be moved as the gear 3 rotates. The term "closely facing" includes a case where the inner circumferential surface of the gear accommodating opening 223 and the tooth tip of the gear 3 face each other with a gap therebetween, as well as a case where they are in contact with each other.

[0023] The inner peripheral surface of the gear accommodating opening 223 includes a pair of arcuate surfaces 223a formed by the diameter of the tooth tip circle of the gear 3 centered on each of the gears 3, an upper surface 223b formed by a plane parallel to the left-right direction connecting the pair of arcuate surfaces 223a, and a U-shaped lower surface 223c extending downward connecting the pair of arcuate surfaces 223a. The space surrounded by the lower surface 223c communicates with the outlet hole 234 of the support plates 23, 24.

[0024] The main body portion 221 is formed with a plurality of through holes 224 for fixing the pair of support plates 23, 24, the back plate 25, and the discharge plate 26. The plurality of through holes 224 penetrate from the front surface to the rear surface of the housing main body 22. The plurality of through holes 224 are formed at intervals around the gear accommodating opening 223.

[0025] The protruding portion 222 protrudes upward from the main body portion 221. The protruding portion 222 is formed in a substantially rectangular shape. Supply ports 225 that communicate with the gear chamber 21 are formed on the upper end surface and the left and right end surfaces of the protruding portion 222. That is, three supply ports 225 are formed in the protruding portion 222. Each supply port 225 is connected to a supply path 226, and the supply path 226 is connected to the upper surface 223b of the gear accommodating opening 223. As a result, each supply port 225 communicates with the gear chamber 21 via the supply path 226.

[0026] The gear pump 1 according to this embodiment has a plurality of supply ports 225, so that the fluid supply unit 6 can be connected to one of the three supply ports 225 and a flow meter can be connected to the other supply ports 225. Furthermore, the unused one or two supply ports 225 are closed with a blind plug or the like. Although three supply ports 225 are formed in this embodiment, one or two supply ports 225 may be formed.

[0027] The material of the housing body 22 is not particularly limited, and examples thereof include stainless steel alloys, tungsten-based steel, and molybdenum-based steel.

[0028] (Support plates 23, 24) The support plates 23, 24 are plates that support the rotating shafts 41, 42. As shown in Fig. 5, the pair of support plates 23, 24 are arranged on both sides of the housing main body 22 in the front-rear direction. Of the pair of support plates 23, 24, the support plate arranged in front of the housing main body 22 is defined as the "first plate 23," and the support plate arranged in the rear of the housing main body 22 is defined as the "second plate 24."

[0029] (Plate 1 23) The first plate 23 faces the front surface of the housing main body 22. The first plate 23 includes a plate main body 231 and a gear-facing portion 232, as shown in FIG.

[0030] The plate main body 231 is a portion of the first plate 23 that is fixed to the housing main body 22. As shown in FIG. 7(A), the plate main body 231 has a plurality of fixing holes 2311 and an opening 2312. The plurality of fixing holes 2311 are holes used when fixing to another adjacent member. The "other adjacent member" here refers to the housing main body 22. However, if another plate is interposed between the plate main body 231 and the housing main body 22, the other plate may also be considered the "other adjacent member." When the plate main body 231 is placed on the housing main body 22, a fastener is passed through the fixing hole 2311 and the through-hole 224, thereby fixing the plate main body 231 to the housing main body 22.

[0031] The opening 2312 is formed in a portion facing the end face of the gear 3. When viewed in the front-to-rear direction, the opening 2312 is formed in a substantially elliptical shape formed by connecting a pair of circles having the same diameter as the tooth tip circle centered on the rotation axis of each gear 3 with two parallel tangents. The gear facing portion 232 described below is fitted into the opening 2312.

[0032] On the surface of the plate body 231 facing the housing body 22, the outer circumferential edge is located closer to the housing body 22 than the portion where the fixing holes 2311 are formed, along the entire periphery. Specifically, the thickness of the plate body 231 is thicker at the outer circumferential edge than at the portion where the fixing holes 2311 are formed. The difference in thickness between the outer circumferential edge and the portion where the fixing holes 2311 are formed is, for example, preferably 1 μm or more and 10 μm or less, and more preferably 3 μm or more and 5 μm or less. As a result, when the plate body 231 is fixed to the housing body 22, the outer circumferential edge of the plate body 231 makes strong contact with the housing body 22, thereby reducing fluid leakage from between the housing body 22 and the plate body 231.

[0033] The material of the plate body 231 is not particularly limited, and examples thereof include metals such as stainless steel alloys, tungsten-based steel, and molybdenum-based steel.

[0034] The gear opposing portion 232 is a portion of the first plate 23 that faces the end face of the gear 3. The gear opposing portion 232 is fitted into an opening 2312 of the plate main body 231. The gear opposing portion 232 is formed to have approximately the same shape and size as the opening 2312. A pair of bearing holes 2321 that support the rotating shafts of the gear 3 are formed in the gear opposing portion 232. The bearing holes 2321 receive the rotating shafts 41, 42 while rubbing against them. In this way, the gear opposing portion 232 rotatably supports the rotating shafts 41, 42.

[0035] The gear opposing portion 232 is harder than the plate main body 231. The gear opposing portion 232 according to this embodiment is a plate made of a superhard material. The superhard material is an alloy formed by sintering and bonding one or more powders of carbides of aluminum (Al), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), and tungsten (W) with one or more powders of iron-group metals, i.e., iron (Fe), cobalt (Co), and nickel (Ni). Hereinafter, the powder used for the superhard material may be referred to as "superhard material powder." Because the gear opposing portion 232 is made of a material harder than the plate main body 231, wear on the housing 2 caused by the rotation of the gear 3 can be reduced compared to a case where the gear opposing portion 232 is made of only the plate main body 231.

[0036] The gear opposing portion 232 is positioned vertically and horizontally relative to the plate main body 231, but is merely fitted in and not fixed. In other words, the gear opposing portion 232 can move in the front-to-rear direction relative to the plate main body 231. However, in the present invention, the gear opposing portion 232 may be fixed to the plate main body 231. Furthermore, a watertight structure may be formed between the gear opposing portion 232 and the plate main body 231.

[0037] A pressure relief portion 233 that suppresses the trapping phenomenon is formed in the gear opposing portion 232. The pressure relief portion 233 is formed on one of the main surfaces of the gear opposing portion 232, on a surface (opposing surface) that faces the end face of the gear 3. The pressure relief portion 233 includes a first relief groove 2331 that extends from the meshing portion 31 of the pair of gears 3 toward the suction space 211, and a second relief groove 2332 that extends from the meshing portion 31 toward the discharge space 212. The first relief groove 2331 and the second relief groove 2332 are separated from each other and are not connected to each other.

[0038] Here, the trapping phenomenon refers to a phenomenon in which fluid is trapped in a blocked area formed by the gear opposing portion 232 and the tooth surface of the gear 3 at the meshing portion 31 of the gear 3, adversely affecting pump performance. The pressure relief portion 233 allows the fluid remaining in the meshing portion 31 of the gear 3 to escape, thereby reducing the adverse effects of the trapping phenomenon.

[0039] A pair of lubrication grooves 2333 are formed in the gear opposing portion 232. The lubrication grooves 2333 extend linearly from the bearing hole 2321 to the suction space 211. By flowing lubricating oil into each lubrication groove 2333, it is possible to supply lubricating oil to the end face of the gear 3 and between each of the rotating shafts 41, 42 and the bearing hole 2321.

[0040] The first plate 23 has an outlet hole 234. The outlet hole 234 is a hole in the first plate 23 that allows the fluid sent from the gear chamber 21 to pass forward. When the first plate 23 is viewed from the front to the rear (i.e., when viewed along the rotation axis direction), the outlet hole 234 is formed at a position offset from the meshing portion 31 of the pair of gears 3. The outlet hole 234 according to this embodiment is located below the meshing portion 31 with respect to the straight line connecting the rotation axes of the pair of gears 3. In other words, the outlet hole 234 is located below the meshing portion 31. More specifically, when viewed in the front-rear direction, the center of the outlet hole 234 is formed below the meshing portion 31 and at a position the same distance from the rotation axes of the pair of gears 3. The outlet hole 234 is formed across the plate main body 231 and the gear opposing portion 232.

[0041] (Plate 24) The second plate 24 faces the rear surface of the housing main body 22. The second plate 24 includes a plate main body 241 and a gear-facing portion 242, as shown in FIG.

[0042] The plate main body 241 is a portion of the second plate 24 that is fixed to the housing main body 22. As shown in FIG. 7(B), the plate main body 241 has a plurality of fixing holes 2411 and an opening 2412. The gear opposing portion 242 is also formed with a pressure relief portion 243 that suppresses the trapping phenomenon. The pressure relief portion 243 has a first relief groove 2431 that extends from the meshing portion 31 of the pair of gears 3 toward the suction space 211, and a second relief groove 2432 that extends from the meshing portion 31 toward the discharge space 212. The gear opposing portion 242 is also formed with a pair of lubrication grooves 2433. The second plate 24 has the same structure as the first plate 23 except that it does not have the outlet hole 234. Therefore, detailed descriptions of each component will be omitted.

[0043] (Backplate 25) 5, the back plate 25 faces the rear surface of the second plate 24. The back plate 25 is formed with an insertion hole 251 through which one of the rotation shafts 41 passes, and a plurality of fixing holes 252. Each of the insertion hole 251 and the fixing holes 252 penetrates the back plate 25 from the front surface to the rear surface.

[0044] (Discharge plate 26) 5, the discharge plate 26 faces the front surface of the first plate 23. The discharge plate 26 has a plurality of fixing holes 261, a discharge port 262, and a flow path 263 (FIG. 9) that connects the outlet hole 234 of the first plate 23 and the discharge port 262.

[0045] The multiple fixing holes 261 are holes used when fixing to the housing main body 22. The fixing holes 261 of the discharge plate 26 communicate with the fixing holes 2311 of the first plate 23, the through holes 224 of the housing main body 22, the fixing holes 2411 of the second plate 24, and the fixing holes 252 of the back plate 25, and by passing fixing tools through them, the housing main body 22, the pair of support plates 23 and 24, the back plate 25, and the discharge plate 26 are fixed to one another.

[0046] The discharge port 262 is an opening in the gear pump 1 through which the fluid supplied to the gear chamber 21 is discharged. In this embodiment, as shown in Fig. 9(B), when the gear pump 1 is viewed in the front-rear direction (i.e., the direction of the rotation axis), the discharge port 262 is located on a line connecting the pair of rotation shafts 41, 42 and between the pair of rotation shafts 41, 42. As a result, the discharge port 262 is formed at a position that overlaps with the centroid of the discharge plate 26 when the discharge plate 26 is viewed in the front-rear direction.

[0047] In this specification, "located on a straight line" means that at least a portion of the outlet 262 overlaps with the rotation shafts 41 and 42. Therefore, even if the center of the outlet 262 is deviated from the straight line connecting the rotation shafts 41 and 42, as long as part of the outlet 262 is located on the straight line, it falls within the category of "located on the straight line connecting the rotation shafts 41 and 42."

[0048] As shown in Fig. 10, the flow path 263 connects the discharge port 262 and the outlet hole 234. As shown in Fig. 9(A), the flow path 263 is composed of a recessed groove 263a extending upward and a discharge hole 263b connected to the recessed groove 263a and extending in the front-rear direction. As shown in Fig. 10, the outlet hole 234 is located in front of the discharge space 212 and below the pair of rotation shafts 41, 42. However, in this embodiment, because the flow path 263 is formed with a crank-shaped cross section, the discharge port 262 can be located at a position overlapping with the centroid of the discharge plate 26 when the discharge plate 26 is viewed in the front-rear direction.

[0049] (rotation axis) The rotating shafts 41, 42 are supported by a pair of support plates 23, 24. As shown in Fig. 8, the rotating shafts 41, 42 protrude in the front-rear direction from the end face of each gear 3. The portions of the rotating shafts 41, 42 protruding from the end faces of the gears 3 are inserted through the bearing holes 2321 of the first plate 23 and the bearing holes 2421 of the second plate 24.

[0050] The gear pump 1 according to this embodiment includes a pair of rotating shafts, a drive shaft 41 and a driven shaft 42. The drive shaft 41 is a rotating shaft connected to the drive unit 5. The axial direction of the drive shaft 41 extends in the front-rear direction. The driven shaft 42 is a rotating shaft parallel to the drive shaft 41. The driven shaft 42 is aligned in the left-right direction relative to the drive shaft 41. The drive shaft 41 and the driven shaft 42 are rotatably supported by the support plates 23, 24.

[0051] The rotating shafts 41 and 42 include a shaft substrate and a coating layer formed on the surface of the shaft substrate by thermal spraying of a superhard material. Examples of materials for the shaft substrate include stainless steel alloys, tungsten-based steels, and molybdenum-based steels. The superhard coating layer is formed by spraying superhard powder onto the shaft substrate using a thermal spray gun, for example. This provides the rotating shaft with higher hardness than a rotating shaft without a superhard coating layer, reducing deformation or breakage of the rotating shaft even when excessive torque is applied to the rotating shaft.

[0052] (Gear 3) The pair of gears 3 are housed in the gear chamber 21 in a state where they mesh with each other. One gear 3 (drive gear) of the pair of gears 3 is fixed to the drive shaft 41. The other gear 3 (driven gear) is fixed to the driven shaft 42. As a result, the pair of gears 3 are rotatably supported by the support plates 23, 24.

[0053] The gear 3 has an involute tooth profile. However, the gear 3 according to the present invention does not have to have an involute tooth profile, and may have a special tooth profile such as a sinusoidal tooth profile, a segmented gear, a tocolute tooth profile, a cycloid tooth profile, a sucroid tooth profile, a trochoid tooth profile, or an elliptical tooth profile.

[0054] The pair of gears 3 are made of the same superhard material as the gear opposing portion 232. This reduces wear of the gear 3 as it rotates. The gear 3 and the gear opposing portion 232 may be made of the same material or different materials. In the present invention, the material of the gear 3 is not limited to superhard material, and may be made of other metals.

[0055] 3, when the pair of gears 3 rotate, the fluid supplied from the supply port 225 passes through the suction space 211, enters the space surrounded by adjacent teeth of the gear 3 and the inner circumferential surface of the gear housing opening 223, and is sent to the discharge space 212. The fluid that has moved to the discharge space 212 is sent to the discharge port 262 through the outlet hole 234 and the flow path 263. The fluid that comes out from the discharge port 262 is sent to the fluid discharge unit 7.

[0056] (Fluid discharge section 7) 1, the fluid discharge part 7 is attached to the discharge port 262 of the gear pump 1 and discharges the fluid toward the object to be coated. The fluid discharge part 7 includes a nozzle 71 and a nozzle attachment part 72 that attaches the nozzle 71 to the gear pump 1.

[0057] The nozzle 71 extends forward from the position of the discharge port 262. The nozzle 71 is disposed at a position overlapping the centroid of the discharge plate 26 when viewed in the front-rear direction. An elastic body is provided at the tip of the nozzle 71. Examples of elastic bodies include elastomers, fluororesins (e.g., PTFE, PFA, FEP, ETFA, PVDF, etc.), and natural rubber. The elastic body constitutes the tip of the nozzle 71. The elastic body may be coated on the tip of the nozzle body that constitutes the main body of the nozzle 71, or a cylindrical elastic body may be attached to the tip of the nozzle body. Examples of materials for the nozzle body include aluminum, stainless steel, fluororesin, and brass. When the nozzle body is made of fluororesin, an elastic body need not be provided at the tip. Furthermore, depending on the object to be coated, a nozzle 71 with or without an elastic body may be used. By providing elasticity at the tip of the nozzle 71, damage to the object to be coated can be reduced even if the nozzle 71 comes into contact with the object to be coated, and the fluid can be drained off more smoothly.

[0058] The nozzle mounting portion 72 mounts the nozzle 71 to the discharge plate 26 with the nozzle 71 communicating with the discharge port 262. There are no particular limitations on the method of mounting the nozzle mounting portion 72 to the discharge plate 26, and the method can be achieved by, for example, screwing, fitting, inserting, screwing, bolting, pinning, welding, etc. In this embodiment, the nozzle mounting portion 72 is mounted to the discharge plate 26 by screwing.

[0059] Furthermore, the nozzle attachment portion 72 removably holds the base end portion of the nozzle 71 with a cap nut, which allows the nozzle 71 to be easily replaced.

[0060] (Fluid supply section 6) The fluid supply unit 6 is connected to a fluid supply source and supplies fluid to the gear pump 1. The fluid supply unit 6 is attached to a supply port 225 of the housing body 22. For example, a pressure sensor 61, a swivel joint, a coupling, etc. are connected to the fluid supply unit 6 as appropriate. Note that the pressure sensor 61 may be connected to another supply port 225.

[0061] (Drive unit 5) The drive unit 5 drives the gear pump 1. As shown in FIG. 1 , the drive unit 5 includes a motor 51 and a reducer 52. The power of the motor 51 is transmitted to the drive shaft 41 via the reducer 52. The drive unit 5 rotates the drive shaft 41, thereby driving the gear pump 1.

[0062] The motor 51 is not particularly limited, and examples thereof include an electric motor, an air motor, and a hydraulic motor.

[0063] <Action and effect> As described above, in the gear pump 1 according to this embodiment, the support plates 23, 24 include the plate bodies 231, 241 and the gear-facing portions 232, 242 fitted into the openings of the plate bodies 231, 241. The gear-facing portions 232, 242 are harder than the plate bodies 231, 241. Therefore, the plate bodies 231, 241, which require the machining of the fixing holes 2311, 2411, can be made of an easily machined material, while the gear-facing portions 232, 242, which face the gear 3, can be made of a wear-resistant material. In other words, when there is fluid between the portion of the housing 2 facing the gear 3 and the end face of the gear 3, wear is unlikely to occur in the portion of the housing 2 facing the gear 3, even if the gear 3 rotates.

[0064] Furthermore, by partially providing the gear-facing portions 232, 242 in the support plates 23, 24, the processability is better than if the support plates 23, 24 were made of a hard material entirely, and costs can also be reduced.

[0065] Furthermore, because the gear opposing portions 232, 242 are plates made of a superhard material, wear is unlikely to occur even if a highly viscous fluid gets between the end face of the gear 3 and the gear opposing portions 232, 242 when the gear 3 rotates. In the unlikely event that wear does occur, it is possible to replace only the plates made of superhard material. Furthermore, because the support plates 23, 24 are partially made of a superhard material, the overall weight of the gear pump 1 can be reduced compared to when the entire support plates 23, 24 are made of a superhard material. As a result, a gear pump 1 that is both wear-resistant and lightweight can be achieved.

[0066] Furthermore, since the rotating shafts have a coating material layer formed by super-hard thermal spraying, bending and deformation of the rotating shafts 41 and 42 can be reduced.

[0067] Furthermore, in this embodiment, when viewed along the rotation axis direction (front-rear direction), the discharge port 262 is located on a straight line connecting the pair of rotation shafts 41, 42 and between the pair of rotation shafts 41, 42, so that during operation, the user can easily grasp the positions of the discharge port 262 and the nozzle 71. For example, when the gear pump coating device 100 according to this embodiment is attached to a robot arm and used, an action such as inserting the nozzle 71 into a small gap may be memorized during teaching. Even in this case, since the discharge port 262 is located in the center of the tip surface, there is an advantage that the positions of the discharge port 262 and the nozzle 71 are easy to grasp and teaching is easy to perform.

[0068] <Modification> The above embodiment is merely one of various embodiments of the present invention. The embodiment can be modified in various ways depending on the design, etc., as long as the object of the present invention can be achieved. Modifications of the embodiment are listed below. The modifications described below can be applied in appropriate combinations.

[0069] The gear pump 1 according to the above embodiment is used in the coating device 100, but is not limited to this and may be used as a pump for, for example, liquid delivery, metering, pressurization, spinning, tank transfer, additive mixing, branching, etc.

[0070] In the above embodiment, the rotating shafts rotate along the inner peripheral surfaces of the bearing holes 2321, 2421 of the support plates 23, 24, but in the present invention, the rotating shafts 41, 42 may be fixed to the support plates 23, 24, and the gear 3 may rotate relative to the rotating shafts 41, 42. In this case, a gear 3 incorporating a bearing may be used.

[0071] In the gear pump 1 according to the above embodiment, the support plates 23, 24 are provided with a first plate 23 and a second plate 24, but in the present invention, the support plate may be provided with only one of the first plate 23 and the second plate 24.

[0072] The openings 2312, 2412 of the plate bodies 231, 241 in the above embodiments penetrate from the front surface to the rear surface of the plate bodies 231, 241, but the openings 2312, 2412 may also be recesses recessed from the surface facing the gear chamber 21 and having a bottom surface.

[0073] In this specification, expressions accompanied by "approximately", such as "approximately parallel" or "approximately perpendicular", may be used. For example, "approximately parallel" means that the state is substantially "parallel", and includes not only a strictly "parallel" state but also an error of a few degrees. The same applies to other expressions accompanied by "approximately".

[0074] Furthermore, in this specification, expressions such as "end" and "edge" are used that are distinguished by the presence or absence of "... part." For example, "edge" means the end of an object, while "edge" means a region having a certain range that includes the "edge." Any point within a certain range that includes the edge is considered to be an "end." The same applies to other expressions that include "... part." [Explanation of symbols]

[0075] 100 painting equipment 1 gear pump 2. Housing 23 First plate (support plate) 231 Plate body 2311 Fixing hole 2312 Opening 232 Gear opposing part 233 Pressure relief section 234 Exit hole 24 Second plate (support plate) 241 Plate body 2411 Fixing hole 2412 Opening 242 Gear opposing part 243 Pressure relief section 26 Discharge plate 262 Discharge port 263 Channel 3 gears 31 Engagement part 41 Drive shaft (rotating shaft) 42 Driven shaft (rotating shaft) 5 Drive unit

Claims

1. A pair of gears that mesh with each other; a pair of rotation shafts protruding from end surfaces of the pair of gears; a housing that rotatably supports the pair of gears via the pair of rotation shafts, the housing having a discharge port that discharges the fluid sent by the pair of gears; Equipped with the housing has a support plate that supports the pair of rotation shafts, The support plate is a plate body including a fixing hole for fixing to another adjacent member and an opening formed in a portion facing the end faces of the pair of gears; a gear opposing portion that is fitted into the opening to support the pair of rotation shafts and that faces end surfaces of the pair of gears; Including, the gear opposing portion is harder than the plate body, The support plate is an outlet hole through which the fluid sent by the pair of gears passes, the outlet hole being formed at a position offset from the meshing portion of the pair of gears when viewed along the rotation axis direction; the discharge port is located on a straight line connecting the pair of rotation shafts and between the pair of rotation shafts when viewed along the rotation shaft direction, the housing has a discharge plate including a flow passage communicating the discharge port and the outlet hole; Gear pump.

2. The gear opposing portion is a plate made of a superhard material.

2. The gear pump according to claim 1.

3. The rotating shaft has a coating material layer formed by superhard thermal spraying. The gear pump according to claim 1 or 2.

4. The gear opposing portion has a pressure relief portion formed on an opposing surface opposing the end surfaces of the pair of gears, which suppresses the trapping phenomenon. The gear pump according to any one of claims 1 to 3.

5. the pair of gears comprising superhard material; The gear pump according to any one of claims 1 to 4.

6. A gear pump according to any one of claims 1 to 5; a drive unit that drives one of the pair of gears in the gear pump; Equipped with Gear pump type painting equipment.

Images