JP5833797B1 - Negative pressure pump and manufacturing method thereof - Google Patents

Abstract

A resin-made housing body formed in a bottomed cylindrical shape having an opening on one side and having a bottom surface and an inner peripheral surface defining a pump chamber inside, and welded to the inner peripheral surface to close the opening A resin housing cover, and a vane that is slidably supported by a rotor that is rotationally driven with a position eccentric from the center of the pump chamber as a rotation axis, and that partitions the pump chamber, and the inner peripheral surface is The housing cover can be brought into contact with the vane when the housing cover is welded to the inner peripheral surface.

Description

  The present invention relates to a negative pressure pump that applies negative pressure to a brake booster or the like, and a method for manufacturing the same.

  As a negative pressure pump for applying a negative pressure to a brake booster or the like, a negative pressure pump using the rotation of an engine is used. The negative pressure pump is connected to a housing body in which a pump chamber is formed, a housing cover attached to the housing body so as to close the pump chamber, a vane for partitioning the pump chamber, a camshaft of an engine, and the like. And a rotor to be rotated. However, in such a negative pressure pump, there is a problem that the pump efficiency is lowered due to air leaking from the gap between the housing body and the housing cover and the vane.

  Therefore, conventionally, a metal material is used for each constituent member of the negative pressure pump, and the dimensional accuracy of each constituent member is increased by machining such as cutting, so that a clearance between the housing body and the housing cover and the vane is reduced. Making it small is performed (for example, refer patent document 1).

Japanese Patent No. 4600654 JP 2013-241906 A

  However, when a metal material is used for each constituent member to increase the dimensional accuracy of each constituent member, there is a problem that the manufacturing cost increases.

  Therefore, by manufacturing the housing main body and the housing cover by resin injection molding, the cost can be reduced compared to the case of manufacturing them by metal machining.

  However, injection molding has lower dimensional accuracy than machining. For this reason, when the housing body and the housing cover are manufactured by injection molding, there is a problem that the gap between the housing body and the housing cover and the vane becomes larger than when the housing body and the housing cover are manufactured by machining. For example, when manufactured by machining, the tolerance range of dimensional tolerance can be reduced to about 0.1 mm. On the other hand, when manufactured by injection molding, the tolerance range of dimensional tolerance becomes as large as about 0.2 mm.

  In addition, as described in Patent Document 2, it is also possible to reduce the gap between the housing body and the housing cover and the vane by arranging the side plate between the housing body and the housing cover and the vane. It is done. However, when the housing body and the housing cover are made of resin, the sliding resistance between the side plate and the vane is increased by such a method. For this reason, there also exists a problem that the drive resistance of a negative pressure pump increases.

  Accordingly, an object of one aspect of the present invention is to provide a negative pressure pump capable of reducing variation in pump efficiency while suppressing an increase in cost, and a method for manufacturing the same.

  The negative pressure pump according to one aspect of the present invention is formed in a bottomed cylindrical shape having an opening on one side, and a resin-made housing body in which a bottom surface and an inner peripheral surface defining a pump chamber are formed inside, A resin housing cover that is welded to the inner peripheral surface to close the opening of the pump chamber, a rotor that is rotationally driven with the position eccentric from the center of the pump chamber as a rotation axis, and a pump that is slidably supported by the rotor. And the inner peripheral surface has a shape that allows the housing cover to abut against at least one of the vane and the rotor when the housing cover is welded to the inner peripheral surface.

  In the negative pressure pump according to one aspect of the present invention, the pump chamber defined by the housing body and the housing cover is partitioned by the vanes. The vane is slidably supported by a rotor that is rotationally driven with a position eccentric from the center of the pump chamber as a rotation axis. Therefore, the negative pressure can be generated by rotating the vane in the pump chamber by rotating the rotor and expanding and contracting the plurality of spaces in the pump chamber partitioned by the vane. And since a housing main body and a housing cover are resin, compared with the case where these are metal, cost can be reduced.

  Moreover, the inner peripheral surface of the housing body has a shape that allows the housing cover to abut against at least one of the vane and the rotor when the housing cover is welded. For this reason, when the housing cover is welded to the housing body, the housing cover is abutted against the vane, whereby a gap between at least one of the vane and the rotor abutted against the housing cover and the housing body and the housing cover is temporarily provided. Can be zero. For this reason, by adjusting the housing cover return amount thereafter, the gap between the housing body and the housing cover and the vane can be adjusted with high accuracy even if the dimensional accuracy of the housing body and the housing cover is not high. . Thereby, variation in pump efficiency can be reduced while suppressing an increase in cost.

  In the negative pressure pump, when the vane comes into contact with the bottom surface, the inner peripheral surface is located on the side opposite to the bottom surface of the vane from the edge opposite to the bottom surface of the inner peripheral surface in the depth direction of the pump chamber. It may be flush to the position beyond the plane. By forming the inner peripheral surface of the housing body in this manner, the housing cover can be abutted against the vane when the housing cover is welded to the inner peripheral surface. In addition, the position exceeding the surface opposite to the bottom surface of the vane refers to a position on the bottom surface side of the surface opposite to the bottom surface of the vane.

  In the negative pressure pump, the inner peripheral surface may be flush with the depth direction of the pump chamber. By forming the inner peripheral surface of the housing body in this manner, the housing cover can be abutted against the vane when the housing cover is welded to the inner peripheral surface. Moreover, since the inner peripheral surface is flush with the depth direction of the pump chamber, the airtightness between the inner peripheral surface and the vane can be enhanced. Thereby, pump efficiency improves compared with the case where the inner peripheral surface is not flush with the depth direction of the pump chamber.

  A method of manufacturing a negative pressure pump according to one aspect of the present invention is a resin housing formed in a bottomed cylindrical shape having an opening on one side and having a bottom surface and an inner peripheral surface defining a pump chamber inside. A main body, a resin housing cover that is welded to the inner peripheral surface to block the opening of the pump chamber, a rotor that is rotationally driven with a position eccentric from the center of the pump chamber as a rotation axis, and slidably supported by the rotor And a vane for partitioning the pump chamber, a vane housing step of housing the vane in the pump chamber of the housing body, and after the vane housing step, inserting the housing cover into the opening, A welding step of welding the housing cover to the inner peripheral surface, wherein the welding step inserts the housing cover into the inner peripheral surface and pushes the housing cover into at least one of the vane and the rotor. With bright butting process.

  In the method for manufacturing a negative pressure pump according to one aspect of the present invention, after performing the vane housing step of housing the vane in the pump chamber of the housing main body, the housing cover is welded when the housing cover is welded to the housing main body. The abutting step of abutting the at least one of the vane and the rotor is performed. Thereby, the clearance gap between at least one of the vane and rotor which abutted against the housing cover, and the housing main body and the housing cover can be once made zero. For this reason, by adjusting the return amount of the housing cover, the gap between the housing body and the housing cover and the vane can be adjusted with high accuracy without increasing the dimensional accuracy of the housing body and the housing cover. . Thereby, variation in pump efficiency can be reduced while suppressing an increase in cost.

  In the negative pressure pump manufacturing method, the welding step may further include a pulling back step of pulling the housing cover back to the opposite side of the bottom surface after the abutting step. Thus, the return amount of the housing cover can be adjusted with high accuracy by pulling the housing cover back to the opposite side of the bottom surface by the pulling back process after the abutting process. Thereby, the clearance gap between a housing main body and a housing cover, and a vane can be adjusted with still higher precision.

  According to one aspect of the present invention, variation in pump efficiency can be reduced while suppressing an increase in cost.

It is a perspective view of the negative pressure pump concerning a 1st embodiment. It is a disassembled perspective view of the negative pressure pump concerning a 1st embodiment. It is sectional drawing in the III-III line shown in FIG. It is sectional drawing in the IV-IV line shown in FIG. FIG. 4 is a partially enlarged view of FIG. 3. It is a figure which shows the manufacturing process of the negative pressure pump which concerns on 1st Embodiment. It is a figure which shows the manufacturing process of the negative pressure pump which concerns on 2nd Embodiment. It is a perspective view of the negative pressure pump concerning a 3rd embodiment. FIG. 10 is a partially enlarged view of FIG. 9. It is a figure which shows the manufacturing process of the negative pressure pump which concerns on 3rd Embodiment.

  Embodiments of a negative pressure pump and a manufacturing method thereof according to one aspect of the present invention will be described below with reference to the drawings. The negative pressure pump according to the embodiment is a negative pressure pump that is connected to a cam shaft (not shown) or the like of an engine (not shown) and generates negative pressure by rotational driving of the cam shaft. However, the present invention does not limit the rotational drive source of the negative pressure pump, and the rotational drive force may be obtained from other than the camshaft. In addition, the same code | symbol is attached | subjected about the element which is the same or it corresponds in each figure, and the overlapping description is abbreviate | omitted.

[First Embodiment]
FIG. 1 is a perspective view of a negative pressure pump according to the first embodiment. FIG. 2 is an exploded perspective view of the negative pressure pump according to the first embodiment. 3 is a cross-sectional view taken along the line III-III shown in FIG. 4 is a cross-sectional view taken along line IV-IV shown in FIG. FIG. 5 is a partially enlarged view of FIG. As shown in FIGS. 1 to 5, the negative pressure pump 1 according to the first embodiment includes a housing 2, a rotor 3, and a vane 4.

  The housing 2 includes a resin housing main body 21 having an opening 26 on one side, and a resin housing cover 22 that closes the opening 26 of the housing main body 21.

  The housing body 21 is formed in a bottomed cylindrical shape (cup shape) having an opening 26 on one side. A concave portion 27 that defines the pump chamber A is formed inside the housing body 21. The concave surface portion 27 includes a bottom surface 27 a that defines the bottom surface of the pump chamber A and an inner peripheral surface 27 b that defines the outer peripheral surface of the pump chamber A. An opening 26 is formed at a position facing the bottom surface 27a. Here, a direction perpendicular to the bottom surface 27a and directed from the opening 26 toward the bottom surface 27a (right direction in FIGS. 3 and 5) is referred to as a depth direction B of the pump chamber A.

  The bottom surface 27a is formed in a substantially circular plane shape. Note that the substantially circular shape of the bottom surface 27a includes not only a perfect circle but also an ellipse, a deformed circle, and the like.

  The inner peripheral surface 27b rises perpendicularly from the peripheral edge of the bottom surface 27a with respect to the bottom surface 27a. The inner peripheral surface 27 b is formed flush with the pump chamber A in the depth direction B. That is, the inner peripheral surface 27b is formed in a straight line having no irregularities from the edge 27c on the opening 26 side (the side opposite to the bottom surface 27a) to the edge 27d on the bottom surface 27a side in the depth direction B of the pump chamber A. Has been. For this reason, the pump chamber A defined by the housing body 21 is a space having a substantially circular cross section of the same shape in the depth direction B of the pump chamber A.

  The housing body 21 is formed with a first through-hole 23, a second through-hole 24, and a third through-hole 25 that pass through the housing body 21 and communicate with the pump chamber A. The first through port 23 is a through port for applying the negative pressure in the pump chamber A to a brake booster (not shown). The first through-hole 23 communicates with the brake booster from the inner peripheral surface 27b. The second through hole 24 is a through hole for discharging the air in the pump chamber A into a cylinder head cover (not shown) of an engine (not shown). The second through hole 24 is communicated with the cylinder head cover from the bottom surface 27a. The third through hole 25 is a through hole for inserting the rotor 3 into the pump chamber A. The third through hole 25 is communicated with the cylinder head cover from the bottom surface 27a. The third through hole 25 is formed in a circular cross section, and can support the rotor 3 rotatably. Further, the center of the third through-hole 25 is located at a position eccentric from the center of the pump chamber A (bottom surface 27a).

  The housing cover 22 has the same outer shape as the inner peripheral surface 27 b of the housing body 21, and is welded to the inner peripheral surface 27 b while being inserted into the opening 26. The housing cover 22 is formed in a substantially disc shape having a front surface 22a and a back surface 22b having the same shape as the bottom surface 27a, and an outer peripheral surface 22c connected to the outer peripheral edge of the front surface 22a and the outer peripheral edge of the back surface 22b. The outer peripheral surface 22 c of the housing cover 22 is welded to the inner peripheral surface 27 b of the housing body 21. The rear surface 22 b of the housing cover 22 defines the top surface of the pump chamber A.

  A grip portion 22 d for gripping the housing cover 22 by a chuck (not shown) is formed on the surface 22 a of the housing cover 22. The grip portion 22d may have any shape as long as it can be gripped by the chuck. For example, as shown in the drawing, the grip portion 22d may be formed by a raised portion extending radially from the center of the surface 22a.

  A bead 22e for performing vibration welding described later is formed on the outer peripheral surface 22c of the housing cover 22. The bead 22e is a part protruding from the outer peripheral surface 22c. The bead 22e is formed integrally with the housing cover 22 from the same resin material. The bead 22e is preferably formed continuously on the entire circumference of the outer peripheral surface 22c, but may be intermittently (partially) formed on the outer peripheral surface 22c.

  Although the manufacturing method of the housing main body 21 and the housing cover 22 is not specifically limited, For example, resin injection molding can be adopted. The resin used as the material for the housing body 21 and the housing cover 22 is not particularly limited. From the viewpoint of welding the housing body 21 and the housing cover 22, the resin of the housing body 21 and the resin of the housing cover 22 are preferably the same type. In the case where different types of welding are possible, the housing body 21 and the housing cover 22 may be made of different materials. Further, from the viewpoint of heat resistance, polyamide (PA) or polyphthalamide (PPA) can be employed. Among these, it is preferable to employ polyamide from the viewpoint of cost. From the viewpoint of strength, it is preferable to disperse chopped strands such as glass fibers in the resin, or to impregnate the resin with fiber fabrics such as glass fibers.

  The welding of the housing cover 22 to the housing body 21 is not particularly limited, but can be performed by, for example, vibration welding. The vibration welding can be performed as follows, for example. First, a welding bead 22 e is formed on the outer peripheral surface 22 c of the housing cover 22. Then, after aligning the housing cover 22 with the opening 26, the housing cover 22 is pressed toward the bottom surface 27 a side while applying ultrasonic vibration to the housing cover 22. As a result, the bead 22 e is melted and the housing cover 22 is inserted into the concave portion 27 from the opening 26. Then, application of ultrasonic vibration and pressurization are stopped, and the molten resin is cooled and cured. As a result, the outer peripheral surface 22 c of the housing cover 22 is welded to the inner peripheral surface 27 b of the housing body 21.

  The rotor 3 is a member that rotates about an axis perpendicular to the bottom surface 27 a of the housing body 21 and the back surface 22 b of the housing cover 22 as a rotation axis C. The rotor 3 is inserted into the connecting chamber 31 connected to the camshaft of the engine, a central support 32 inserted into the third through-hole 25 and rotatably supported by the housing body 21, and inserted into the pump chamber A. And a support end portion 33 that slidably supports the vane 4.

  The connecting end 31 is connected to the camshaft via a connecting member 34. The connecting end portion 31 is adapted to transmit the rotational drive of the camshaft via the connecting member 34. The center support part 32 is formed in a cylindrical shape. The central support portion 32 is rotatably supported by the housing body 21 via a bush 36 that is press-fitted into the third through hole 25 of the housing body 21. The support end 33 is formed in a cylindrical shape. The support end 33 is formed with a support groove 35 into which the vane 4 is inserted. The support groove 35 is a groove cut out along a straight line that passes through the central axis of the support end 33 and is orthogonal to the central axis. For this reason, the support end portion 33 can slidably support the vane 4 in a direction passing through the rotation axis of the support end portion 33 and perpendicular to the central axis line by inserting the vane 4 into the support groove 35. It is possible.

  And the connection end part 31, the center support part 32, and the support end part 33 are connected in series so that the center axis line of the connection end part 31, the center support part 32, and the support end part 33 may correspond. For this reason, the central axis of the support end 33 is the rotation axis C of the rotor 3. As described above, the center of the third through hole 25 is located at a position eccentric from the center of the pump chamber A (bottom surface 27a). For this reason, the rotation axis C of the rotor 3 is at a position eccentric from the center of the pump chamber A. Further, the direction passing through the central axis of the support end 33 and orthogonal to the central axis is the radial direction of the rotor 3. The radial direction of the rotor 3 is also referred to as the rotational radial direction of the rotor 3.

  The vane 4 is a member that is accommodated in the pump chamber A and partitions the pump chamber A. The vane 4 includes a partition part 41, a first contact part 42, and a second contact part 43. The partition 41 is a member for partitioning the pump chamber A. The partition 41 is formed in a rectangular flat plate shape that is long in the length direction that is the radial direction of the rotor 3 and short in the thickness direction perpendicular to the length direction. The partition 41 extends in the radial direction of the rotor 3 and partitions the pump chamber A. The 1st contact part 42 and the 2nd contact part 43 are members which adjoin or contact | abut to the internal peripheral surface 27b. The first contact portion 42 is inserted into one end portion of the partition portion 41 so as to be freely drawn out in the longitudinal direction of the partition portion 41. The second contact portion 43 is inserted into the other end portion of the partition portion 41 opposite to the first contact portion 42 so as to be drawn out in the longitudinal direction of the partition portion 41. For this reason, the first abutting portion 42 is pulled out in the direction opposite to the second abutting portion 43 along the longitudinal direction of the partition portion 41 when centrifugal force is exerted by the rotation of the rotor 3. Similarly, the second abutting portion 43 is pulled out in the direction opposite to the first abutting portion 42 along the longitudinal direction of the partition portion 41 when centrifugal force is exerted by the rotation of the rotor 3.

  Next, a manufacturing method of the negative pressure pump 1 according to the first embodiment will be described with reference to FIG.

  FIG. 6 is a diagram illustrating a manufacturing process of the negative pressure pump according to the first embodiment. As shown in FIG. 6, when manufacturing the negative pressure pump 1, first, as shown in FIG. 6A, a vane housing step of housing the vane 4 in the pump chamber A of the housing body 21 is performed. In the vane housing step, first, the rotor 3 is inserted into the third through hole 25 of the housing body 21 via the bush 36 so that the rotor 3 is rotatably supported with respect to the housing body 21. Next, the vane 4 is accommodated in the pump chamber A through the opening 26 of the housing body 21, and the vane 4 is inserted into the support groove 35 of the rotor 3. Thereby, the accommodation of the vane 4 in the pump chamber A is completed. When the vane housing step is completed, the housing cover 22 is gripped by the chuck 5 and disposed near the opening 26 of the housing body 21.

  Next, as shown in FIGS. 6B and 6C, a welding step of inserting the housing cover 22 into the opening 26 of the housing body 21 and welding the housing cover 22 to the inner peripheral surface 27 b of the housing body 21. I do.

  In the welding process, first, as shown in FIG. 6B, an abutting process is performed in which the housing cover 22 is inserted into the opening 26 and the housing cover 22 is abutted against at least one of the vane 4 and the rotor 3. Next, as shown in FIG. 6C, a pulling back process is performed for pulling the housing cover 22 back to the opposite side (opening 26 side) of the bottom surface 27a.

  In the abutting process, first, the housing cover 22 is aligned with the opening 26. Then, the housing cover 22 is pressed toward the bottom surface 27 a side while applying ultrasonic vibration to the housing cover 22. The pressing of the housing cover 22 toward the bottom surface 27 a can be performed by moving the housing cover 22 in the depth direction B of the pump chamber A. Then, the bead 22 e is melted by vibration friction, and the housing cover 22 is inserted into the concave surface portion 27 through the opening 26.

  Here, since the inner peripheral surface 27b is formed flush with the depth direction B of the pump chamber A, if the housing cover 22 is continuously pressed against the bottom surface 27a while applying ultrasonic vibration to the housing cover 22, the housing The cover 22 is inserted into the concave portion 27 until it abuts against at least one of the vane 4 and the rotor 3 without being inhibited by the inner peripheral surface 27b. In other words, the inner peripheral surface 27b is arranged such that the bottom surface 27a of the vane 4 extends from the edge opposite to the bottom surface 27a of the inner peripheral surface 27b in the depth direction of the pump chamber A when the vane 4 contacts the bottom surface 27a. It will be flush to the position beyond the opposite surface. For this reason, it can be said that the inner peripheral surface 27b has a shape that allows the housing cover 22 to abut against at least one of the vane 4 and the rotor 3 when the housing cover 22 is welded to the inner peripheral surface 27b. The portion of the rotor 3 against which the housing cover 22 abuts becomes a support end portion 33 inserted into the pump chamber A.

  By the way, when designing the vane 4 and the rotor 3, a predetermined dimensional tolerance is set for the vane 4 and the rotor 3. For this reason, when the vane 4 and the rotor 3 are manufactured, ideally, the surface opposite to the bottom surface 27a of the vane 4 and the rotor 3 is flush. However, in practice, the surface opposite to the vane 4 and the bottom surface 27a of the rotor 3 is not flush. That is, the vane 4 is higher than the rotor 3 or the rotor 3 is higher than the vane 4. The vane 4 being higher than the rotor 3 means that the surface of the vane 4 opposite to the bottom surface 27a is located farther from the bottom surface 27a than the surface of the rotor 3 opposite to the bottom surface 27a. That the rotor 3 is higher than the vane 4 means that the surface on the opposite side to the bottom surface 27a of the rotor 3 is located farther from the bottom surface 27a than the surface on the opposite side to the bottom surface 27a of the vane 4. Therefore, in consideration of the dimensional tolerances of the vane 4 and the rotor 3, the housing cover 22 is abutted against at least one of the vane 4 and the rotor 3 in the abutting process. However, it is preferable that the housing cover 22 is abutted against the vane 4 in the abutting step.

  When the housing cover 22 hits at least one of the vane 4 and the rotor 3, the pressing of the housing cover 22 is stopped. As a result, the gap between at least one of the vane 4 and the rotor 3 abutted against the housing cover 22 and the housing main body 21 and the housing cover 22 becomes zero. The determination as to whether the housing cover 22 has come into contact with either the vane 4 or the rotor 3 can be made based on, for example, a detection value of a pressure sensor attached to the chuck 5.

  In the pulling back process, the housing cover 22 is pulled back in the direction opposite to the depth direction B of the pump chamber A by the chuck 5. As a result, a gap is formed between at least one of the vane 4 and the rotor 3 abutted against the housing cover 22 and the housing main body 21 and the housing cover 22. At this time, the pullback amount of the housing cover 22 is set so that the gap between the housing main body 21 and the housing cover 22 and the vane 4 has a predetermined length.

  Here, if the gap between the housing main body 21 and the housing cover 22 and the vane 4 is too large, the compressed air leaks from the gap between the housing main body 21 and the housing cover 22 and the vane 4, and the pump efficiency decreases. To do. On the other hand, if this gap is too small, the sliding resistance between the housing body 21 and the housing cover 22 and the vane 4 increases, and the driving resistance of the negative pressure pump increases. Therefore, the pullback amount of the housing cover 22 is set so that the optimum gap length is obtained in the relationship between the pump efficiency and the driving resistance of the negative pressure pump.

  When the housing cover 22 is pulled back by a predetermined pullback amount, the ultrasonic vibration applied to the housing cover 22 is stopped, and the gripping of the housing cover 22 by the chuck 5 is released. As a result, the molten resin is cooled and cured, and the outer peripheral surface 22c of the housing cover 22 is welded to the inner peripheral surface 27b of the housing body 21 as shown in FIGS.

  As described above, in this embodiment, the pump chamber A defined by the housing body 21 and the housing cover 22 is partitioned by the vane 4, and the position where the vane 4 is eccentric from the center of the pump chamber A is defined as the rotation axis C. The rotor 3 is rotationally driven and is slidably supported. For this reason, the negative pressure can be generated by rotating the vane 4 in the pump chamber A by rotating the rotor 3 and expanding and contracting the two spaces of the pump chamber A partitioned by the vane 4. And since the housing main body 21 and the housing cover 22 are resin, cost can be reduced compared with the case where these are metal.

  Moreover, the inner peripheral surface 27b of the housing body 21 is formed flush with the depth direction B of the pump chamber A, so that the housing cover 22 can be attached to at least the vane 4 and the rotor 3 when the housing cover 22 is welded. The shape can be abutted on one side. Therefore, when the negative pressure pump 1 is manufactured, after performing the vane housing step of housing the vane 4 in the pump chamber A of the housing body 21, the welding step of welding the housing cover 22 to the housing body 21 is performed. An abutting step of abutting the housing cover 22 against at least one of the vane 4 and the rotor 3 is performed. As a result, the gap between at least one of the vane 4 and the rotor 3 abutted against the housing cover 22 and the housing main body 21 and the housing cover 22 becomes zero once. For this reason, the housing cover 22 is pulled back to the opposite side of the bottom surface 27a, and the return amount of the housing cover 22 is adjusted, so that the housing body 21 and the housing cover 22 can be accommodated without increasing the dimensional accuracy. The gaps between the main body 21 and the housing cover 22 and the vanes 4 can be adjusted with high accuracy. Thereby, variation in pump efficiency can be reduced while suppressing an increase in cost.

[Second Embodiment]
Next, a second embodiment will be described. The second embodiment is basically the same as the first embodiment, and only the welding process is different from the first embodiment. For this reason, in the following description, only matters different from the first embodiment will be described, and description similar to that of the first embodiment will be omitted.

  FIG. 7 is a diagram illustrating a manufacturing process of the negative pressure pump according to the second embodiment. As shown in FIG. 7, when the negative pressure pump 1 is manufactured in the second embodiment, first, the vane accommodation step shown in FIG. 7A is performed as in the first embodiment. 7A is the same as FIG. 6A.

  Next, as shown in FIGS. 7B and 7C, a welding step of inserting the housing cover 22 into the opening 26 of the housing body 21 and welding the housing cover 22 to the inner peripheral surface 27 b of the housing body 21. I do.

  In the welding process, as shown in FIGS. 7B and 7C, the abutting process is performed in which the housing cover 22 is inserted into the opening 26 and the housing cover 22 is abutted against at least one of the vane 4 and the rotor 3. .

  In the abutting process, first, the housing cover 22 is aligned with the opening 26. Then, the housing cover 22 is pressed toward the bottom surface 27 a side while applying ultrasonic vibration to the housing cover 22. At this time, the vicinity of the central portion of the housing cover 22 is held by the chuck 5. Then, the bead 22e is melted by friction, so that the housing cover 22 enters the concave surface portion 27 of the housing body 21. The holding position of the housing cover 22 by the chuck 5 may be any position as long as it is other than the peripheral edge of the housing cover 22.

  Here, since the housing cover 22 is made of resin, the housing cover 22 is bent by pressing the housing cover 22 toward the housing body 21. In other words, the vicinity of the center portion of the housing cover 22 is pressed by the chuck 5, but the peripheral edge portion of the housing cover 22 generates a sliding resistance with the inner peripheral surface 27b. For this reason, the peripheral portion of the housing cover 22 moves toward the bottom surface 27a side behind the central portion of the housing cover 22.

  Therefore, as shown in FIG. 7B, when the vicinity of the center portion of the housing cover 22 hits at least one of the vane 4 and the rotor 3, in the depth direction B of the pump chamber A (see FIGS. 3 and 5). When the positional deviation between the vicinity of the center of the housing cover 22 and the peripheral edge of the housing cover 22 reaches a predetermined length, the pressing of the housing cover 22 is stopped and the ultrasonic vibration applied to the housing cover 22 is stopped. Then, as shown in FIG. 7C, the holding of the housing cover 22 by the chuck 5 is released. Then, the central portion of the housing cover 22 that has been abutted against at least one of the vane 4 and the rotor 3 is released from the pressing force by the chuck 5 and is therefore pulled back to the opposite side of the bottom surface 27a. Accordingly, at least one of the vane 4 and the rotor 3 abutted against the housing cover 22 and the housing main body 21 and the housing cover 22 by a positional deviation between the vicinity of the center portion of the housing cover 22 and the peripheral edge portion of the housing cover 22. A gap is formed between them. At this time, the pressure of the housing cover 22 and the ultrasonic waves are set so that the gap between the housing body 21 and the housing cover 22 and the vane 4 has an optimum gap length in relation to the pump efficiency and the driving resistance of the negative pressure pump. The timing for stopping the application of vibration and releasing the grip of the housing cover 22 by the chuck 5 is set.

  In this state, the molten resin is cooled and cured, and the outer peripheral surface 22c of the housing cover 22 is welded to the inner peripheral surface 27b of the housing main body 21 as shown in FIGS.

  As described above, in this embodiment, the housing body 21 and the gap between the housing cover 22 and the vane 4 are formed by utilizing the elastic deformation of the housing cover 22. Thereby, even if it does not perform the drawing-back process like 1st Embodiment, the clearance gap between the housing main body 21 and the housing cover 22, and the vane 4 can be adjusted with high precision.

[Third Embodiment]
Next, a third embodiment will be described. The third embodiment is basically the same as the first embodiment, and differs from the first embodiment only in the shape of the inner peripheral surface of the housing body. For this reason, in the following description, only matters different from the first embodiment will be described, and description similar to that of the first embodiment will be omitted.

  FIG. 8 is a perspective view of a negative pressure pump according to the third embodiment. FIG. 9 is a partially enlarged view of FIG. As shown in FIGS. 8 and 9, in the negative pressure pump 1 ′ according to the third embodiment, the inner peripheral surface 27b ′ of the housing body 21 includes a first inner peripheral surface portion 271b positioned on the bottom surface 27a side, and a bottom surface 27a. And a second inner peripheral surface portion 272b located on the opposite side (opening 26 (see FIG. 2) side of the housing main body 21).

  The first inner peripheral surface portion 271b rises perpendicularly to the bottom surface 27a from the periphery of the bottom surface 27a. The first inner peripheral surface portion 271 b is formed flush with the pump chamber A in the depth direction B. When the vane 4 comes into contact with the bottom surface 27a, the first inner peripheral surface portion 271b extends from the edge 27d on the bottom surface 27a side of the inner peripheral surface 27b ′ in the direction opposite to the depth direction B of the pump chamber A. The vane 4 extends to a position not reaching the surface 4a opposite to the bottom surface 27a. In this case, the position that does not reach the surface 4a opposite to the bottom surface 27a of the vane 4 refers to a position closer to the bottom surface 27a than the surface 4a opposite to the bottom surface 27a of the vane 4.

  The second inner peripheral surface portion 272b extends in a direction perpendicular to the bottom surface 27a at a position where the diameter is increased all around the first inner peripheral surface portion 271b. The second inner peripheral surface portion 272 b is formed flush with the depth direction B of the pump chamber A. The second inner peripheral surface portion 272b has an edge on the opposite side (opening 26 side) of the inner peripheral surface 27b ′ in the depth direction B of the pump chamber A when the vane 4 comes into contact with the bottom surface 27a. 27c extends to a position exceeding the surface 4a opposite to the bottom surface 27a of the vane 4. In this case, the position exceeding the surface 4a opposite to the bottom surface 27a of the vane 4 refers to a position closer to the bottom surface 27a than the surface 4a opposite to the bottom surface 27a of the vane 4.

  That is, when the vane 4 comes into contact with the bottom surface 27a, the length D of the second inner peripheral surface portion 272b in the depth direction B of the pump chamber A is the surface of the vane 4 from the edge 27c of the inner peripheral surface 27b ′. It is longer than the length E reaching 4a. Further, when the vane 4 comes into contact with the bottom surface 27a, the length D ′ of the first inner peripheral surface portion 271b in the direction opposite to the depth direction B of the pump chamber A is the bottom surface 27a of the inner peripheral surface 27b ′. It is shorter than the length E ′ from the side edge 27d to the surface 4a of the vane 4.

  The housing cover 22 ′ has basically the same shape as the housing cover 22 of the first embodiment, but has the same outer shape as the second inner peripheral surface portion 272b, not the same outer shape as the first inner peripheral surface portion 271b. Yes.

  Next, a manufacturing method of the negative pressure pump 1 'according to the third embodiment will be described with reference to FIG.

  FIG. 10 is a diagram illustrating manufacturing steps of the negative pressure pump according to the third embodiment. As shown in FIG. 10, when manufacturing the negative pressure pump 1 ′, first, as shown in FIG. 10A, the same vane housing process as that of the first embodiment is performed. Next, as shown in FIGS. 10B and 10C, the same welding process as in the first embodiment is performed.

  Here, the inner peripheral surface 27 b ′ of the housing main body 21 ′ has a shape different from that of the housing main body 21 of the first embodiment. However, the inner peripheral surface 27b ′ is flush with the second inner peripheral surface portion 272b located on the opposite side of the bottom surface 27a from the end edge 27c of the inner peripheral surface 27b ′ to the position beyond the surface 4a of the vane 4. . That is, the inner peripheral surface 27b ′, like the inner peripheral surface 27b of the first embodiment, pushes the housing cover 22 against at least one of the vane 4 and the rotor 3 when the housing cover 22 is welded to the inner peripheral surface 27b ′. It has a shape that can be applied.

  For this reason, in the welding process, as shown in FIG. 10B, the housing cover 22 is inserted into the opening 26, and the abutting process of abutting the housing cover 22 against at least one of the vane 4 and the rotor 3 is performed. Can do. Further, as shown in FIG. 10C, a pulling back step of pulling the housing cover 22 back to the opposite side of the bottom surface 27a can be performed.

  Thus, in the third embodiment, when the inner peripheral surface 27b ′ welds the housing cover 22 to the inner peripheral surface 27b ′ in the same manner as the inner peripheral surface 27b of the first embodiment, the vane 4 And it has a shape that can abut against at least one of the rotor 3. For this reason, as in the first embodiment, the clearance between the housing body 21 ′ and the housing cover 22 and the vane 4 can be adjusted with high accuracy. Thereby, variation in pump efficiency can be reduced while suppressing an increase in cost.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

  For example, in the above-described embodiment, the shape of the inner peripheral surface of the housing body is specifically specified, but this inner peripheral surface is attached to at least one of the vane and the rotor when the housing cover is welded to the inner peripheral surface. Any shape may be used as long as it can be abutted. For example, the inner peripheral surface does not necessarily need to be flush. Moreover, since it should just be a shape which can be air-tightly welded with the outer peripheral surface of a housing cover, the shape where the opening edge part was chamfered may be sufficient. Moreover, the taper shape by which diameter is reduced toward the bottom face of a concave part may be sufficient.

  For example, in the embodiment described above, one vane is accommodated in the pump chamber and the pump chamber is divided into two spaces by the vane. However, the number of vanes, the number of spaces partitioning the pump chamber, and the like are as follows. It is not particularly limited.

  In addition, the above three embodiments can be appropriately combined. For example, the negative pressure pump of the third embodiment may be manufactured by the manufacturing method of the second embodiment.

DESCRIPTION OF SYMBOLS 1 ... Negative pressure pump, 2 ... Housing, 21 ... Housing main body, 22 ... Housing cover, 22a ... Front surface, 22b ... Back surface, 22c ... Outer peripheral surface, 22d ... Holding part, 22e ... Bead, 23 ... First through-hole, 24 2nd through-hole, 25 ... 3rd through-hole, 26 ... opening, 27 ... concave surface part, 27a ... bottom surface, 27b ... inner peripheral surface, 271b ... first inner peripheral surface part, 272b ... second inner peripheral surface part, 27c ... End edge, 27d ... edge, 3 ... rotor, 31 ... connection end, 32 ... center support, 33 ... support end, 34 ... connection member, 35 ... support groove, 36 ... bush, 4 ... vane, 4a ... Surface: 41 ... Partition part, 42 ... First contact part, 43 ... Second contact part, 5 ... Chuck, A ... Pump chamber, B ... Depth direction of pump chamber, C ... Rotation axis.

Claims (2)

A resin-made housing body formed in a bottomed cylindrical shape having an opening on one side and having a bottom surface and an inner peripheral surface defining a pump chamber inside, and welded to the inner peripheral surface to close the opening A negative pressure pump comprising: a resin housing cover; a rotor that is rotationally driven with a position eccentric from the center of the pump chamber as a rotation axis; and a vane that is slidably supported by the rotor and partitions the pump chamber. A manufacturing method of
A vane housing step of housing the vane in the pump chamber of the housing body;
After the vane housing step, the housing cover is inserted into the opening, and a welding step of welding the housing cover to the inner peripheral surface is provided,
The welding step includes an abutting step of inserting the housing cover into the inner peripheral surface and abutting the housing cover against at least one of the vane and the rotor.
Manufacturing method of negative pressure pump. The welding step further includes a pulling back step of pulling the housing cover back to the opposite side of the bottom surface after the abutting step.
The manufacturing method of the negative pressure pump of Claim 1 .

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