JP2012017659A - Uniaxial eccentric screw pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a uniaxial eccentric screw pump capable of performing control of dimensions in an axial direction at the time of assembling a stator regardless of an accumulated error by the part.SOLUTION: In the uniaxial eccentric screw pump, the stator 4 is composed of one rubber stator inner cylinder 4a, and two metal stator outer cylinders 4b and 4c having a cylindrical part 4e fitted to the outside of the stator inner cylinder 4a and an end face part 4d disposed at the end part of the cylindrical part 4e, facing two axial ends of the stator inner cylinder 4a, and has ring-shaped stator packings 12 and 14 disposed on both the suction side and the discharge side in a manner to seal the gap between opposed surfaces of the end face part 4d of the stator outer cylinders 4b and 4c and the two axial ends 4t of the stator inner cylinder 4a. The stator packing 12 and 14 is configured in a manner to position the axial direction of the stator 4 by being sandwiched by the two stator outer cylinders 4b and 4c from both the suction side and the discharge side, and interposed.

Description

  The present invention relates to a uniaxial eccentric screw pump for quantitatively pumping viscous liquids such as food raw materials, chemical raw materials, and sewage sludge, and more particularly to a stator support structure of this type of uniaxial eccentric screw pump.

  As this type of single-shaft eccentric screw pump, there is one in which a male-screw-shaped rotor is housed in a fixed stator having a female-thread-shaped inner surface, and the rotor is connected to a drive shaft via a universal joint (for example, Patent Documents). 1 (see FIG. 1). According to this single-shaft eccentric screw pump, by rotating the drive shaft, the rotor can be eccentrically moved while rotating with respect to the shaft center of the stator, whereby fluid can be pumped from the suction side to the discharge side.

  However, the single-shaft eccentric screw pump described in the same document requires a universal joint to be interposed between the drive shaft and the rotor because the rotation axis of the rotor revolves around the stator axis, and the structure is complicated. In particular, there is a problem of cleaning the dead space of the universal joint, especially in the case of food pressure feeding, and there is a problem that cleaning cannot be performed unless the universal joint is disassembled. In addition, the universal joint hinders the inflow of transported goods in the suction part on the suction side, and the revolution of the rotor has also caused vibration.

Therefore, in order to solve these problems, as disclosed in Patent Document 2, a male screw rotor directly connected to the drive shaft and a bearing are rotatably supported without using a universal joint. In addition, a single-shaft eccentric screw pump has been developed that includes a stator having a female-threaded inner surface whose rotational axis is eccentric with respect to the rotational axis of the rotor.
As shown in FIG. 3, the uniaxial eccentric screw pump described in this document has a stator 104 having a rubber stator inner cylinder 104a, and two stator outer cylinders at both ends in the axial direction on the outer periphery of the stator inner cylinder 104a. 104b and 104c are attached. The stator 104 is rotatably supported by self-lubricating bearings 5 and 6, and the externally threaded rotor 2 fixed to the drive shaft 3 is decentered by a predetermined distance E from the axis L 1 of the stator 4. It is configured.

JP 59-153992 A JP 2009-293529 A

However, the uniaxial eccentric screw pump described in this document has a structure in which a thrust load applied to the stator 104 is received by the opposing surfaces of the two stator outer cylinders 104b and 104c and the self-lubricating bearings 5 and 6 and the self-lubricating bearings 5 and 6. The length B between the axially opposed surfaces that receive the thrust load in the self-lubricating bearings 5 and 6 is the axial length of the stator 104, the self-lubricating bearings 5 and 6, and the two stator outer cylinders 104b and 104c. It will be determined by the cumulative dimension. Therefore, for example, when managing the length B between the axially facing surfaces as a management dimension at the time of assembly in the same figure, in order to perform the accurate dimension management, the cumulative error of each axial length is determined for each part. There was a problem that it had to be managed with high accuracy.
Therefore, the present invention has been made paying attention to such problems, and is a single-shaft eccentric screw that can easily manage the axial dimension when assembling the stator, regardless of the cumulative error in each component unit. The purpose is to provide a pump.

  In order to solve the above-described problems, the present invention is directed to a male threaded rotor that is directly connected to a drive shaft, and is rotatably supported via a slide bearing, and its rotational axis is eccentric with respect to the rotational axis of the rotor. A single-shaft eccentric screw pump that pumps fluid from the suction side to the discharge side by performing an eccentric motion with respect to the axis of the stator while the rotor rotates. The stator is provided with a single stator inner cylinder made of rubber, a cylindrical portion fitted on the outside of the stator inner cylinder, and an end portion of the cylindrical portion, and is opposed to both axial end portions of the stator inner cylinder. It is composed of two metal stator outer cylinders having end face portions, and the suction side and the discharge side are sealed so as to seal between the facing surfaces of the end face portions of the stator outer cylinders and both end portions in the axial direction of the stator inner cylinder. Each of the stator packings is sandwiched by two stator outer cylinders from both the suction side and the discharge side, thereby positioning the stator in the axial direction. It is characterized by the structure.

  According to the stator supporting structure of the uniaxial eccentric screw pump according to the present invention, the annular stator packing is sandwiched from both the suction side and the discharge side of the stator inner cylinder by the two stator outer cylinders. Due to the redundancy of the axial length due to the elastic deformation of the stator packing, it is not necessary to adjust the length between the opposed surfaces that receive thrust load due to the accumulated error in each component unit, which was required in the past. Dimensional control in the axial direction can be facilitated.

Here, in the single-shaft eccentric screw pump according to the present invention, each of the suction-side and discharge-side stator outer cylinders is provided with a threaded portion including a male thread and a female thread that are threaded along the mutual axial direction. It is preferable that the stator outer cylinders on the suction side and the discharge side are connected to each other by the joint.
With such a configuration, both ends of the stator inner cylinder can be sandwiched by tightening the male and female screws on the suction side and the discharge side of the stator outer cylinder, so that a seal is provided between the stator outer cylinder and the inner cylinder. In addition, the axial direction of the stator can be positioned, and the two stator outer cylinders on the suction side and the discharge side and the stator inner cylinder can be easily connected and integrated.

Further, in the single-shaft eccentric screw pump according to the present invention, the rubber surface of the stator inner cylinder is provided over the entire surface of both axial ends, and the suction side and the discharge side are replaced with the above-described stator packing. The rubber surfaces of both ends of the stator inner cylinder are directly sandwiched between the two stator outer cylinders from both ends, thereby sealing between the stator outer cylinder and the inner cylinder with the rubber stator inner cylinder end surface itself and It is preferable to position the axial direction.
With such a configuration, the stator outer cylinder and the inner cylinder are sealed without using the above-described stator packing, and a thrust load is generated due to a cumulative error in each component unit that has been conventionally required. It is not necessary to adjust the length between the opposing surfaces, and the dimension management in the axial direction when the stator is assembled can be facilitated.

  As described above, according to the uniaxial eccentric screw pump according to the present invention, it is possible to easily manage the dimensions in the axial direction when the stator is assembled, regardless of the accumulated error in each component unit.

BRIEF DESCRIPTION OF THE DRAWINGS It is a side view of one Embodiment of the uniaxial eccentric screw pump which concerns on this invention, In the same figure, the principal part is shown in the cross section along an axis line. It is a side view of the modification of one Embodiment of the uniaxial eccentric screw pump which concerns on this invention. It is a side view of the conventional uniaxial eccentric screw pump, The principal part is illustrated in the cross section along an axis line in the figure.

Hereinafter, a first embodiment of the present invention will be described with reference to the drawings as appropriate.
As shown in FIG. 1, the uniaxial eccentric screw pump 1 has a bracket 11 in which a motor (not shown) is accommodated. The bracket 11 has a housing on a surface 11a on the drive shaft side of a motor (not shown). 7 is installed. The housing 7 includes a suction portion 7a, a main body portion 7b, and a discharge portion 7c in order from the suction side (the right side in the figure). A suction port 8 for pumping fluid is formed in the suction portion 7a of the housing 7, and a discharge port 9 for pumping fluid is formed in the discharge portion 7c. This uniaxial eccentric screw pump 1 includes a housing 2 having a male screw-like rotor 2 and a stator 4 having a female screw-like inner surface.

  The rotor 2 is composed of a spiral portion 2a on the distal end side and a linear base end portion 2b. The base end 2b is directly connected to the motor drive shaft without using a universal joint. On the other hand, the spiral portion 4e has an oval cross section that is eccentric with respect to its own rotation axis L2, and this spiral portion 2a is housed in the stator 4 having a female screw-shaped inner surface. The rotation axis L2 of the rotor 2 is arranged to be eccentric by a predetermined eccentric amount E with respect to the rotation axis L1 of the stator 4.

  Both ends of the stator 4 are rotatably supported in the housing 7 via annular self-lubricating bearings 5 and 6 as sliding bearings. A concave step 7t is formed on the inner peripheral surfaces of the suction portion 7a and the main body portion 7b constituting the housing 7, respectively. Further, on the outer peripheral surface of the stator 4 itself (stator outer cylinders 4b and 4c described later), concave step portions 4u into which the self-lubricating bearings 5 and 6 are fitted are formed at both ends, respectively. The movement of the self-lubricating bearings 5 and 6 in the axial direction is restricted by the portions 4u and 7t.

  Further, the stator 4 has one stator inner cylinder 4a disposed at the center in the axial direction. The stator inner cylinder 4a includes a rubber main body portion 4h and a cylindrical metal housing portion 4g bonded to the outer peripheral surface of the main body portion 4h. The stator inner cylinder 4 a is fixed inside the housing 7 by fitting two metal stator outer cylinders 4 b on the outside thereof. The helical portion 4e formed inside the main body portion 4h has a female thread-like pitch twice that of the helical portion 2a of the rotor 2.

  Each stator outer cylinder 4b includes a cylindrical part 4e fitted in-line with a casing part 4g of the outer side of the stator inner cylinder 4a, and an end face part 4d provided at an end of the cylindrical part 4e on the suction side or the discharge side. Respectively. Between the end face portion 4d of the stator outer cylinder 4b and the end face 4t of the stator inner cylinder 4a (between the mutually opposing surfaces in the axial direction), annular stator packings 12 and 14 are interposed on the suction side and the discharge side, respectively. ing. And the stator inner cylinder 4a (inside the main body part 4h) has its spiral part 4e fixed to the housing part 4g of the stator inner cylinder 4a by a push screw 19, and these rotate integrally.

  Here, the annular stator packings 12 and 14 are interposed between the stator outer cylinders 4b and 4c from both sides of the suction side and the discharge side, whereby the stator outer cylinders 4b and 4c are connected to the stator inner cylinders. A space between the cylinder 4a is sealed by the stator packings 12 and 14, and the stator packing structure is used for positioning the axial direction of the stator 4 by the stator packings 12 and 14.

Next, the operation and effect of the stator support structure of this uniaxial eccentric screw pump will be described.
The single-shaft eccentric screw pump 1 is rotatably supported via a male screw-like rotor 2 directly connected to a drive shaft and self-lubricating bearings 5 and 6, and its rotation axis L 1 is relative to the rotation axis L 2 of the rotor 2. And a stator 4 having a female screw-shaped inner surface arranged eccentrically, and the rotor 2 rotates to perform an eccentric motion with respect to the shaft center of the stator 4 to pump the fluid from the suction side to the discharge side. When the rotor 2 is rotated by the drive shaft 3 of the motor, the rotor 2 rotates about the rotation axis L2, and the stator 4 also rotates about the rotation axis L1 as the spiral portion 2a of the rotor 2 moves. The pumped fluid can be pumped from the suction port 8 to the discharge port 9 by being driven and rotated in synchronism with the rotation.
Therefore, the structure can be made without using a universal joint, so the structure is simple.In particular, in the case of food feeding, the problem of cleaning the dead space of the universal joint is also solved, and the transported goods in the suction part on the suction side are eliminated. Inflow is not obstructed and vibration is small.

  And according to this uniaxial eccentric screw pump, the stator support structure is the stator outer cylinders 4b and 4c mounted on the outer periphery of the stator inner cylinder 4a, and the stator packings 12 and 14 are inserted from both ends of the suction side and the discharge side. Since the stator inner cylinder 4a is sandwiched, the thrust load due to the accumulated error in each component unit, which has been conventionally required, is reduced by the redundancy with respect to the axial length due to the elastic deformation of the interposed stator packings 12 and 14. It is not necessary to adjust the length B between the opposing surfaces of the self-lubricating bearings 5, 6, which is the management dimension when the stator 4 is assembled, and accurate dimension management of the axial position of the stator 4 can be facilitated. .

As described above, according to the stator support structure of the single-shaft eccentric screw pump, it is possible to easily manage the dimensions in the axial direction when the stator is assembled. The single-shaft eccentric screw pump according to the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, FIG. 2 shows a modification.
In the example shown in the figure, the configurations of the stator inner cylinder 4a and the stator outer cylinders 4b and 4c are different from those of the above embodiment. Hereinafter, different points will be described.
As shown in the figure, the stator inner cylinder 4a has a cylindrical casing part 4g whose axial length is shorter than the main body part 4h, and the rubber surface 4f of the main body part 4h of the stator inner cylinder 4a. Is provided over the entire surface at both ends in the axial direction. As a result, the above-described stator packings 12 and 14 are not required, and instead of the stator packings 12 and 14, two stator outer cylinders 4 b and 4 c from both ends of the suction side and the discharge side are rubber at both ends of the stator inner cylinder 4 a. By directly sandwiching the surface 4f, the end surface of the stator inner cylinder 4a made of rubber itself seals between the stator outer cylinders 4b, 4c and the inner cylinder 4a and positions the stator 4 in the axial direction.

With such a configuration, similarly to the above-described embodiment, it is unnecessary to adjust the length between the opposing surfaces that receive the thrust load due to the accumulated error in each component unit, which is conventionally required, and the axially opposing surfaces of the stator It is possible to facilitate accurate dimensional management of the inter-length. In addition to this, the stator outer cylinders 4b, 4c and the inner cylinder 4a can be sealed without using the stator packings 12, 14.
Further, in this modified example, a screw engagement comprising a male screw 16 and a female screw 17 which are screwed along the mutual axial direction to the inner peripheral surface or the outer peripheral surface of each of the stator outer cylinders 4b, 4c on the suction side and the discharge side. A portion 18 is provided. Then, the screwed portion 18 connects the suction-side and discharge-side stator outer cylinders 4b and 4c to each other.

  With such a configuration, the stator inner cylinder 4a can be appropriately sandwiched from both ends in the axial direction by mutual tightening of the male screw 16 and the female screw 17 of the suction-side and discharge-side stator outer cylinders 4b and 4c. it can. Therefore, the stator outer cylinders 4b, 4c and the inner cylinder 4a are sealed and positioned in the axial direction of the stator, and the two stator outer cylinders 4b, 4c on the suction side and the discharge side are connected to the stator inner cylinder 4a. Integration is easy.

  In this modification, the above-described stator packings 12 and 14 are not required, and instead of the stator packings 12 and 14, two stator outer cylinders 4b and 4c are connected to the stator inner cylinder 4a from both ends of the suction side and the discharge side. In the example in which the rubber surfaces at both end portions are directly sandwiched, the example has been described in which the threaded portion 18 is provided in the stator outer cylinders 4b, 4c. In contrast to the above example, the stator outer cylinders 4b and 4c may be combined with a portion provided with the threaded portion 18.

DESCRIPTION OF SYMBOLS 1 Uniaxial eccentric screw pump 2 Rotor 3 Drive shaft 4 Stator 5 Self-lubricating bearing (slide bearing)
6 Self-lubricating bearing (slide bearing)
7 Housing 8 Suction Port 9 Discharge Port 10 Motor 11 Base Bracket 12 (Suction Side) Stator Packing 14 (Discharge Side) Stator Packing 16 Male Screw 17 Female Screw 18 Threaded Portion 19 Push Screw

Claims (3)

An externally threaded rotor directly connected to the drive shaft, and a stator having an internally threaded inner surface that is rotatably supported via a slide bearing and whose rotational axis is arranged eccentrically with respect to the rotational axis of the rotor. A single-shaft eccentric screw pump that pumps fluid from the suction side to the discharge side by performing an eccentric motion with respect to the axis of the stator while the rotor rotates,
The stator includes a single stator inner cylinder made of rubber, a cylindrical portion fitted to the outside of the stator inner cylinder, and an end surface portion provided at an end of the cylindrical portion and opposed to both axial ends of the stator inner cylinder. It is composed of two stator outer cylinders made of metal having
An annular stator packing disposed on each of the suction side and the discharge side so as to seal between the opposed surfaces of the end surface portion of each stator outer cylinder and the axial end portions of the stator inner cylinder;
Each stator packing is sandwiched by two stator outer cylinders from both sides of the suction side and the discharge side, and has a structure for positioning the stator in the axial direction. pump.   Each of the suction-side and discharge-side stator outer cylinders is provided with a threaded portion made up of a male screw and a female screw that are screwed in the axial direction of each other, and the suction-side and discharge-side stator outer cylinders are mutually connected The uniaxial eccentric screw pump according to claim 1, wherein:   The stator inner cylinder is provided with the rubber surfaces extending over the entire surfaces of both axial ends, and without using the stator packing according to claim 1, the stator packing is replaced with the suction side and the discharge side. The rubber surfaces of both ends of the stator inner cylinder are directly sandwiched between the two stator outer cylinders from both ends of the stator, thereby sealing between the stator outer cylinder and the inner cylinder with the rubber stator inner cylinder end surface itself. The uniaxial eccentric screw pump according to claim 1, wherein the axial direction of the uniaxial eccentric screw pump is positioned.

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