JP2015203317A - diaphragm vacuum pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a diaphragm vacuum pump having a chassis structure capable of reducing its manufacturing cost while simplifying manufacturing processes.SOLUTION: A chassis 21 of a diaphragm vacuum pump 11 is formed by coupling a pair of chassis half bodies 22, 23 formed of synthetic resins. Each chassis half body includes base plate parts 22a, 23a having diaphragm mounting portions, and a pair of coupled plate parts protruded from two opposed sides of the base plate parts toward the other chassis half body, respectively. At the front ends of the coupled plate parts, bearing unit holding portions 22c, 23c are provided between which a bearing unit 20 is held for supporting a cam shaft 12a at both ends when both coupled plate parts are coupled at their front ends, respectively.

Description

  The present invention relates to a diaphragm vacuum pump, and more particularly, to a structure of a chassis that supports a drive mechanism of the diaphragm vacuum pump.

  As a diaphragm vacuum pump, a pump chamber that is expanded and contracted by a diaphragm attached to a connecting rod that reciprocates by a crank mechanism provided on a rotating shaft, an intake passage that communicates with the pump chamber via an intake check valve, and an exhaust-side reverse Some have an exhaust passage communicating with a stop valve. In such a diaphragm vacuum pump, a drive mechanism such as a rotating shaft as well as a motor serving as a drive source is supported by the chassis, and the chassis also serves as a casing. (For example, refer to Patent Document 1).

JP-A-6-185466

  The chassis of a conventional diaphragm vacuum pump has been formed into a chassis having the required mechanism and accuracy by machining a highly rigid metal profile or die casting. For this reason, the labor and cost required for machining, etc., and surface treatment may be required.Many manufacturing processes and high processing accuracy are required, which increases the manufacturing cost of the chassis and reduces the price of the diaphragm vacuum pump. It was a factor to raise.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a diaphragm vacuum pump having a chassis structure capable of simplifying the manufacturing process and reducing the manufacturing cost while ensuring the requirements required for the chassis of the diaphragm vacuum pump. It is said.

  In order to achieve the above object, a diaphragm vacuum pump according to the present invention includes a camshaft that rotates integrally with an output shaft of a motor, a crank mechanism that operates by rotation of the camshaft, and an axis line of the camshaft by the crank mechanism. A connecting member that reciprocates in an orthogonal horizontal direction; diaphragms attached to both ends of the connecting member; a pair of pump chambers whose volume is expanded and contracted by the operation of the diaphragm; and an intake passage communicating with each pump chamber; An exhaust passage, an intake side check valve that restricts the backflow of fluid from the pump chamber to the intake passage, and an exhaust side check valve that restricts the backflow of fluid from the exhaust passage to the pump chamber, The camshaft, the crank mechanism, and the connecting member are housed in a rectangular parallelepiped chassis, and the front In the diaphragm vacuum pump in which both ends of the camshaft are respectively held on a pair of opposing walls of the chassis via bearing units, the chassis is formed by combining a pair of chassis halves formed of synthetic resin. The half body includes a base plate portion having a diaphragm mounting portion, and a pair of coupling plate portions projecting from opposite two sides of the base plate portion toward the other chassis half body, and the tip of each coupling plate portion Is characterized in that a bearing unit clamping portion is provided for clamping the bearing unit when the tips of both coupling plate portions are coupled to each other.

  Furthermore, the diaphragm vacuum pump of the present invention is characterized in that each of the chassis halves is formed by an injection compression molding method, and the synthetic resin is PC-GF. Further, each of the chassis halves includes a guide portion for guiding each of the coupling plate portions to a predetermined coupling position at the time of coupling to each of the coupling plate portions, and the bearing unit includes the cam A bearing for rotatably supporting the shaft; and a bearing housing for holding an outer periphery of the bearing. The bearing housing rotates and shafts by engaging with an outer surface of the bearing housing and an inner surface of the bearing unit holding portion. It is characterized in that an engaging portion for preventing the movement of the direction is provided.

  According to the diaphragm vacuum pump of the present invention, by forming a chassis half having a substrate part provided with a pump chamber forming part and a coupling plate part provided with a bearing unit clamping part with a synthetic resin, in particular, PC- By forming a fiber reinforced resin such as GF (glass fiber reinforced polycarbonate) by injection compression molding, a chassis half having excellent dimensional accuracy and strength can be formed. By connecting the two chassis halves in a state where the bearing unit of the camshaft is sandwiched by the bearing unit clamping portion of such a chassis half, the camshaft which is one of the drive mechanisms is rotatably supported and the pump A chassis having a diaphragm mounting portion for forming the chamber can be formed, and a chassis having a predetermined function required for the chassis of the diaphragm vacuum pump can be easily manufactured without machining.

  Further, by providing the guide portion on the coupling plate portion of the chassis half, both the chassis half can be reliably coupled at a predetermined position. Furthermore, the bearing unit can be more reliably supported by the bearing clamping portion by providing the rotation preventing portions that engage with each other on the outer surface of the bearing unit and the inner surface of the bearing clamping portion.

It is a cross-sectional top view of the diaphragm vacuum pump which shows one example of this invention. It is a right view of a diaphragm vacuum pump. It is a front view of a diaphragm vacuum pump. It is a disassembled perspective view of the principal part. It is explanatory drawing of the operating state of a diaphragm vacuum pump.

  As shown in FIGS. 1 to 4, the diaphragm vacuum pump 11 of this embodiment includes a motor 12, a camshaft 12 a that is connected to an output shaft 12 b that protrudes in a horizontal direction from the motor 12, and a camshaft 12 a that rotates. A crank mechanism 13 that is operated by an eccentric cam 13a provided in 12a, a connecting member 14 that is attached to the crank mechanism 13 and reciprocates in a horizontal direction perpendicular to the camshaft 12a, and both ends of the connecting member 14; Attached diaphragms 15 and 16, a pair of pump chambers 17 and 18 whose volume expands and contracts as the diaphragms 15 and 16 advance and retract, and intake passages 17a and 18a and exhaust passages 17b and 18b communicating with the pump chambers 17 and 18, respectively. And the backflow of air from the pump chambers 17 and 18 to the intake passages 17a and 18a is restricted. Intake side check valve 17c, and includes a 18c, exhaust-side check valve 17d to regulate the backflow of air in the exhaust passage 17b, from 18b to the pump chamber 17, and 18d.

  The crank mechanism 13 is mounted orthogonally to the camshaft 12a, and rotates eccentrically with the camshaft 12a and the outer periphery of the eccentric cam 13a via a first bearing 13b. A driven member 13c to be connected and the connecting member 14 connected to the driven member 13c via a second bearing 13d and a connecting pin 13e are provided. The eccentric cam 13a is a circular member attached to the outer periphery of the camshaft 12a, and is arranged at a position different from the central axis of the eccentric cam 13a and the central axis of the camshaft 12a. The driven member 13c is formed in a substantially dharma shape having a large diameter portion 13f formed on one end side and a small diameter portion 13g formed on the other end side, and is attached to an attachment hole formed in the large diameter portion 13f. Further, an eccentric cam 13a is connected via the first bearing 13b, and a connecting pin 13e is attached via a second bearing 13d attached to an attachment hole formed in the small diameter portion 13g, and the connecting pin 13e is connected to the connecting pin 13e. The member 14 is connected.

  The connecting member 14 is formed by joining a frame member 14a that covers one side surface and both end surfaces of the driven member 13c and a plate member 14b that covers the other side surface of the driven member 13c with the driven member 13c interposed therebetween. Is formed with an insertion hole 14c made of a long hole that allows the connecting member 14 to move in the horizontal direction while the camshaft 12a is inserted, and the connecting pin 13e connected to the driven member 13c is fitted to the other end. A connecting pin fitting hole 14d is formed. Furthermore, mounting portions 14e and 14e for mounting the diaphragms 15 and 16 are provided at both ends of the frame member 14a. The horizontal length of the connecting member 14 is such that when one diaphragm 15 is at the top dead center, the other diaphragm 16 is at the bottom dead center, and when the other diaphragm 16 is at the top dead center, It is formed to a length that is the bottom dead center. Further, a balancer (balancing mass) 19 for stably operating the crank mechanism 13 is attached to both sides of the crank mechanism 13 in the camshaft 12a, and a bearing unit 20 is provided at both ends of the camshaft 12a. , 20 are respectively mounted.

  The bearing unit 20 is formed of a bearing 20a that is externally fitted to the camshaft 12a, and a cylindrical bearing housing 20b that holds the outer periphery of the bearing 20a. The outer surface of the bearing housing 20b has a hexagonal rectangular portion 20c and a circular circular portion 20d inscribed in the hexagon, and each vertex of the rectangular portion 20c protrudes from the outer peripheral surface of the circular portion 20d. It has become. In this embodiment, the front end portion of the camshaft 12a is more reliably supported by using a larger bearing on the front end side than the base side (motor side) bearing to prevent precession. ing.

  The crank mechanism 13 formed in this way is accommodated in a rectangular parallelepiped chassis 21. The chassis 21 is formed by joining a pair of chassis halves 22 and 23 formed by injection compression molding of fiber reinforced resin such as PC-GF (glass fiber reinforced polycarbonate). , 23 are a pair of board portions 22a, 23a having a diaphragm attaching portion 21a for attaching the diaphragms 15, 16, respectively, and projecting from opposite two sides of the board portions 22a, 23a toward the other chassis half body. Coupling plate portions 22b and 23b. The substrate portions 22a and 23a are formed in the same shape, whereas the ends of the coupling plate portions 22b and 23b are coupled to the distal ends of the coupling plate portions 22b and 23b, respectively. Bearing unit clamping portions 22c and 23c are provided for clamping and fixing the bearing units 20 and 20 that rotatably support both ends.

  Each of the coupling plate portions 22b and 23b has tip surfaces (divided surfaces) 22d and 23d located at the center between the substrate portions 22a and 23a, and one bearing unit clamping portion 22c is located with respect to the tip surface 22d. The bearing unit 20 is formed in a concave shape having a groove width, and a square groove portion 22e into which a half of the square portion 20c is fitted and a semicircular groove portion into which a half of the circular portion 20d is fitted into the groove bottom portion. 22f. The other bearing unit clamping portion 23c is formed in a convex shape that fits into the concave portion of the one bearing unit clamping portion 22c with respect to the distal end surface 23d, and the other half of the square portion 20c is formed at the distal end portion. A square groove portion 23e into which the circular portion 20d is inserted and a semicircular groove portion 23f into which the other half of the circular portion 20d is inserted are provided. Further, a guide groove 22g along the coupling direction of the coupling plate portions 22b and 23b is provided on the inner surface of the concave portion of the bearing unit clamping portion 22c, and the guide portion 22g is provided on the outer surface of the protruding portion of the bearing unit clamping portion 23c. Guide ridges 23g that fit into the grooves 22g are provided.

  The two coupling plates 22b and 23b are formed by connecting the bearing units 20 and 20 at both ends of the camshaft 12a in the crank mechanism 13 assembled in advance to either of the chassis halves 22 and 23, for example, both coupling plates in one chassis half 22. Both the chassis half bodies 23 are combined while engaging the guide grooves 22g and the guide ridges 23g, after fitting the bearing unit holding portion 22c of the portion 22b with the angle of the square portion 20c. The chassis 21 containing the crank mechanism 13 is formed by inserting the fastening bolts 22i through the bolt insertion portions 22h and 23h provided so as to penetrate the half bodies 22 and 23 and fastening them with nuts.

  As described above, a pair of chassis halves in which the chassis 21 that houses the crank mechanism 13 assembled with the camshaft 12a, the driven member 13c, the connecting member 14, and the like is formed into a preset shape by injection compression molding of fiber reinforced resin. Forming the bodies 22 and 23 together eliminates the need for machining when the chassis is made of metal, and greatly simplifies the manufacturing process when the chassis 21 is manufactured. Further, the bearing units 20 and 20 that support the camshaft 12a are clamped and fixed by the bearing unit clamping portions 22c and 23c provided in the chassis halves 22 and 23, so that the camshaft 12a can be easily attached to the chassis 21. Can be done.

  Furthermore, by providing the guide groove 22g and the guide protrusion 23g at the tip of the coupling plate portions 22b and 23b, the chassis halves 22 and 23 can be reliably coupled in a predetermined assembled state. Further, a square portion 20c and a circular portion 20d are provided on the outer surface of the bearing housing 20b of the bearing unit 20, and a square groove portion 23e and a semicircular groove portion 23f are provided in the bearing unit holding portions 22c and 23c, and these are engaged with each other. In this state, the shaft centers of both bearing units 20 and 20 can be matched, and rotation and axial movement of the bearing housing 20b can be prevented.

  After assembling the chassis 21, the motor 12 having the output shaft 12b connected to one end of the camshaft 12a is fixed to the motor mounting portion 12c provided outside the chassis 21, and the central portions of the diaphragms 15 and 16 are connected to the connecting member. 14 are attached to the attachment portions 14e and 14e at both ends, and the peripheral edge portion is attached to each diaphragm attachment portion 21a of the substrate portions 22a and 23a, and a cover member is provided on the outside of each diaphragm attachment portion 21a via a sealing material 24. 25, and each check valve and each passage are attached to the cover member 25. A motor cover 12d is attached around the motor 12, and a base plate 11b having a rubber cushion 11a on the lower surface is attached.

  At the opening edge of the diaphragm mounting portion 21a opened at the center of each of the substrate portions 22a and 23a, a ring-shaped outer peripheral protrusion 21b protruding outward, and an inner peripheral side of the outer peripheral protrusion 21b, A circumferential groove 21c for attaching the periphery of the diaphragm 15 is formed. The diaphragms 15 and 16 are formed in a disk shape that becomes thinner from the thick central portion attached to the connecting member 14 toward the outer peripheral side, and are formed in the peripheral grooves 21c on the outer peripheral edges of the thin peripheral portions 15a and 16a on the outer peripheral side. Engaging protrusions 15b and 16b to be engaged are respectively formed. The diaphragms 15 and 16 formed in this way are attached to the mounting portion 14e of the connecting member 14 at the center, and the engaging protrusions 15b and 16b are fitted into the circumferential grooves 21c and 21c, and the cover member 25 is provided from the outside. Is attached to the circumferential grooves 21c and 21c in an airtight manner, and the pump chambers 17 and 18 are formed between the outer surfaces of the diaphragms 15 and 16 and the inner surface of the cover member 25. The

  Each cover member 25 includes a flange portion 25a that is airtightly attached to the outer peripheral protrusion 21b of the chassis 21 via a seal member 24, and engagement protrusions 15b and 16b of the diaphragms 15 and 16 that are fitted in the peripheral grooves 21c and 21c. Spherical recesses 25c that respectively form pump chambers 17 and 18 between pressing portions 25b that press the engaging protrusions 15b and 16b into the circumferential grooves 21c and 21c and outer surfaces of the diaphragms 15 and 16, respectively. An intake passage mounting boss portion 25d for attaching the intake passages 17a and 18a, an exhaust passage mounting boss portion 25e for attaching the exhaust passages 17b and 18b, an intake passage mounting boss portion 25d and the pump chambers 17 and 18, respectively. An intake hole 25f for communicating with the exhaust passage mounting boss 25e and the pump chambers 17 and 18, respectively. It is provided.

  The intake passages 17a and 18a are formed by an L-shaped tube having a large-diameter attachment portion fitted into the intake passage attachment boss portion 25d at the base end portion, and in the center of the inner end portion of the large-diameter attachment portion, a pump chamber The intake-side check valves 17c and 18c for restricting the backflow of air from the intake passages 17a and 18a to the intake passages 17a and 18a are integrally attached via seal materials, respectively. The intake passages 17a and 18a have large-diameter attachment portions fitted into the intake passage attachment boss portions 25d, and are airtightly attached to the cover member 25 by a restraining plate 26. The intake passages 17a and 18a are connected to the intake side check valves 17c and 18c. And the pump chambers 17 and 18 through the intake holes 25f and 25f. The exhaust passages 17b and 18b are formed of the same L-shaped tube as the intake passages 17a and 18a, and have a large-diameter attachment portion fitted in the exhaust passage attachment boss portion 25e at the base end portion. Exhaust-side check valves 17d and 18d for restricting the backflow of air from the exhaust passages 17b and 18b to the pump chambers 17 and 18 are integrally formed in the center of the inner end portion of the large-diameter mounting portion via a sealing material. It is attached. The exhaust passages 17b and 18b have large-diameter attachment portions fitted into the exhaust passage attachment boss portions 25e and are hermetically attached to the cover member 25 by the restraining plate 26. The exhaust passages 17b and 18b are exhaust-side check valves 17d and 18d. And the pump chambers 17 and 18 through the exhaust holes 25g and 25g.

  One pump chamber 17 is provided with an intake passage 17a on the motor side and an exhaust passage 17b on the opposite motor side. The other pump chamber 18 has an exhaust passage 18b on the motor side and an intake passage 18a on the opposite motor side. Usually, the exhaust passage 17b of one pump chamber 17 and the intake passage 18a of the other pump chamber 18 are connected to each other by an appropriate connecting pipe 27.

  An operation state when performing an operation of sucking and exhausting gas from the object to be decompressed using the diaphragm vacuum pump 11 will be described with reference to FIG. In FIG. 5, for convenience of explanation, the pump chamber is illustrated in a sectional plan view and the crank mechanism is illustrated in a side view. In the diaphragm vacuum pump 11, the exhaust passage 17 b of one pump chamber 17 and the intake passage 18 a of the other pump chamber 18 are connected by a connecting pipe 28, and the object to be decompressed is connected to the intake passage 17 a of the one pump chamber 17. In this state, the motor 12 is operated. First, as shown in FIG. 5 (A), from the state where one diaphragm 15 is at the bottom dead center and the other diaphragm 16 is at the top dead center, as shown in FIG. 5 (B), along with the camshaft 12a. When the eccentric cam 13a is rotated 90 degrees clockwise, the driven member 13c is driven accordingly, and the connecting member 14 is moved in the horizontal direction toward the one pump chamber 17 so that the one diaphragm 15 is moved to the other. While the volume of the pump chamber 17 is reduced and an exhaust stroke is performed, the other diaphragm 16 expands the volume of the other pump chamber 18 and becomes an intake stroke. Subsequently, as shown in FIG. 5C, when the eccentric cam 13a rotates 180 degrees clockwise, one diaphragm 15 reaches the top dead center and the other diaphragm 16 reaches the bottom dead center. During the period from the state shown in FIG. 5A to the state shown in FIG. 5C, that is, one diaphragm 15 reaches the top dead center from the bottom dead center, and the other diaphragm 16 changes from the top dead center to the bottom dead center. In the meantime, the gas in one pump chamber 17 during the exhaust stroke is exhausted from the exhaust check valve 17d and passes through the exhaust passage 17b, the connecting pipe 28, the intake passage 18a, and the intake check valve 18c. It is sucked into the other pump chamber 18 inside. At this time, in one pump chamber 17, discharge of gas from the pump chamber 17 to the intake passage 17 a is suppressed by the intake side check valve 17 c, and in the other pump chamber 18, exhaust gas is discharged by the exhaust side check valve 18 d. Inhalation of gas from the passage 18b into the pump chamber 18 is suppressed.

  Further, as shown in FIG. 5D, when the eccentric cam 13a rotates 270 degrees clockwise, the connecting member 14 moves horizontally to the other pump chamber 18 side, so that the other diaphragm 16 is moved. While reducing the volume of the pump chamber 18 to the exhaust stroke, one diaphragm 15 increases the volume of the pump chamber 17 to the intake stroke. Next, when the eccentric cam 13a rotates 360 degrees clockwise, as shown in FIG. 5A, one diaphragm 15 reaches the bottom dead center and the other diaphragm 16 reaches the top dead center. During the time from the state of FIG. 5C to the state of FIG. 5A, that is, one diaphragm 15 reaches from the top dead center to the bottom dead center, and the other diaphragm 16 changes from the bottom dead center to the top dead center. In the meantime, the gas from the object to be depressurized is drawn into the one pump chamber 17 during the intake stroke from the intake passage 17a via the intake side check valve 17c, and the gas in the other pump chamber 18 during the exhaust stroke. Is exhausted from the exhaust check valve 18d to the exhaust passage 18b. At this time, in one pump chamber 17, the exhaust-side check valve 17d suppresses the suction of gas from the exhaust passage 17b to the pump chamber 17, and in the other pump chamber 18, the intake-side check valve 18c The discharge of gas from the chamber 18 to the intake passage 18a is suppressed. Thus, by rotating the camshaft 12a by the motor 12, the pump chambers 17 and 18 alternately repeat the intake stroke and the exhaust stroke, and the pressure reducing object is connected in a state where the pump chambers 17 and 18 are connected in series. The exhaust operation can be performed.

  The resin material and the molding method for forming the chassis halves can be appropriately selected according to the conditions such as the strength required for the chassis, and the guide part for joining the chassis halves together is appropriate. It can be provided in an appropriate shape at any position and can be omitted. Further, the rotation of the bearing housing and the prevention of movement in the axial direction are not limited to the hexagonal shape and the inscribed circle described above, and any structure can be adopted, and only press-fitting and fitting are possible. Furthermore, both pump chambers 17 and 18 can be connected and used in parallel.

DESCRIPTION OF SYMBOLS 11 ... Diaphragm vacuum pump, 11a ... Rubber cushion, 11b ... Base plate, 12 ... Motor, 12a ... Cam shaft, 12b ... Output shaft, 12c ... Motor mounting part, 12d ... Motor cover, 13 ... Crank mechanism, 13a ... Eccentric cam , 13b ... first bearing, 13c ... driven member, 13d ... second bearing, 13e ... connecting pin, 13f ... large diameter part, 13g ... small diameter part, 14 ... connecting member, 14a ... frame member, 14b ... plate member, 14c ... Insertion hole, 14d ... Connecting pin insertion hole, 14e ... Mounting part, 15, 16 ... Diaphragm, 15a, 16a ... Thin wall part, 15b, 16b ... Engagement protrusion, 17, 18 ... Pump chamber, 17a, 18a ... Intake air Passage, 17b, 18b ... exhaust passage, 17c, 18c ... intake side check valve, 17d, 18d ... exhaust side check valve, 19 ... balancer, 20 ... Receiving unit, 20a ... bearing, 20b ... bearing housing, 20c ... square part, 20d ... circular part, 21 ... chassis, 21a ... diaphragm mounting part, 21b ... outer peripheral projection, 21c ... peripheral groove, 22, 23 ... half of chassis , 22a, 23a ... substrate portion, 22b, 23b ... coupling plate portion, 22c, 23c ... bearing unit clamping portion, 22d, 23d ... tip surface, 22e, 23e ... square groove portion, 22f, 23f ... semicircular groove portion, 22g ... guide Groove, 23g ... guide protrusion, 22h, 23h ... bolt insertion part, 22i ... fastening bolt, 24 ... sealing material, 25 ... cover member, 25a ... flange part, 25b ... pressing part, 25c ... spherical recess, 25d ... air intake Passage boss part, 25e ... exhaust passage boss part, 25f ... intake hole, 25g ... exhaust hole, 26 ... restraining plate, 27 ... connecting pipe

Claims (5)

  A camshaft that rotates integrally with the output shaft of the motor, a crank mechanism that operates by the rotation of the camshaft, a connecting member that reciprocates in the horizontal direction perpendicular to the axis of the camshaft by the crank mechanism, and the connecting member A pair of diaphragms attached to both ends of each of the first and second pump chambers, a pair of pump chambers whose volume is expanded and contracted by the operation of the diaphragms, an intake passage and an exhaust passage communicating with the pump chambers, An intake-side check valve that regulates backflow; and an exhaust-side check valve that regulates backflow of fluid from the exhaust passage to the pump chamber. The camshaft, the crank mechanism, and the connecting member are formed in a rectangular parallelepiped shape. The camshaft is housed in both ends of the camshaft via a bearing unit. In the diaphragm vacuum pumps respectively held on a pair of opposing walls, the chassis is formed by combining a pair of chassis halves formed of synthetic resin, each chassis half including a substrate portion having a diaphragm mounting portion, A pair of coupling plate portions projecting from the opposite two sides of the board portion toward the other chassis half body, and when the tips of both coupling plate portions are coupled to the tips of each coupling plate portion The diaphragm vacuum pump according to claim 1, further comprising a bearing unit clamping portion for clamping the bearing unit.   The diaphragm vacuum pump according to claim 1, wherein each of the chassis halves is formed by an injection compression molding method.   The diaphragm vacuum pump according to claim 1 or 2, wherein the synthetic resin is PC-GF.   4. Each of the chassis halves is provided with a guide portion for guiding each of the coupling plate portions to a predetermined coupling position at the time of coupling, on each of the coupling plate portions. The diaphragm vacuum pump of any one of Claims.   The bearing unit includes a bearing that rotatably supports the camshaft and a bearing housing that holds an outer periphery of the bearing. The bearing unit engages with an outer surface of the bearing housing and an inner surface of the bearing unit holding portion. The diaphragm vacuum pump according to any one of claims 1 to 4, further comprising an engaging portion for preventing rotation and axial movement of the bearing housing.

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