JP6093116B2 - Vacuum pump - Google Patents

Description

  The present invention relates to a vacuum pump provided with a rotary compression element driven by an electric motor.

Generally, a vacuum pump having a rotary compression element driven by an electric motor in a casing is known. This type of vacuum pump is used, for example, to generate a vacuum for operating a brake booster of an automobile, and can obtain a vacuum by driving a rotary compression element in a cylinder chamber provided in a casing. it can.
By the way, this type of vacuum pump is configured by connecting an electric motor and a casing having a rotary compression element, and the rotary compression element connected to the rotary shaft of the electric motor slides in the cylinder chamber. For this reason, it is important to assemble the casing in accordance with the rotation center of the rotating shaft of the electric motor.
For this reason, conventionally, a fitting hole portion around the rotation center of the rotating shaft is formed on one end side of the case of the electric motor, and a cylindrical fitting portion protruding around the cylinder chamber is formed on the back surface of the casing. The applicant has proposed a vacuum pump that can be accurately and easily aligned at the time of assembling by fitting the fitting portion into the fitting hole portion of the electric motor by inlay fitting. (For example, refer to Patent Document 1).

JP 2011-214519 A

However, in the conventional configuration, when the electric motor and the casing are assembled, a gap is generated between the cylinder chamber and the rotary compression element by the clearance of the fitting tolerance between the fitting hole and the fitting portion. However, individual differences may occur in the performance of the vacuum pump. Further, in the conventional configuration, since the fitting hole is formed in the case of the electric motor and the fitting portion is formed in the casing, separate molds for forming these are required, which increases the manufacturing cost. was there.
Accordingly, the present invention has been made in view of the above-described circumstances, and an object thereof is to provide a vacuum pump that can reduce manufacturing costs, suppress a deviation that occurs during assembly, and exhibit substantially uniform performance. And

To achieve the above object, the present invention provides a vacuum pump having a rotary compression element driven by a motor in a casing, wherein the casing includes a cylinder liner on which the rotary compression element slides, and a rotary shaft of the motor. and a bearing portion for supporting a mounting et is the opening of the bottomed cylindrical motor case body, the casing is provided with a hole in which the cylinder liner is disposed, the back side from the hole open end It is a stepped hole that is reduced in diameter toward .

According to this configuration, the casing includes the cylinder liner on which the rotary compression element slides and the bearing portion that supports the rotation shaft of the motor, and is attached to the opening of the bottomed cylindrical motor case body. The casing includes a hole portion in which the cylinder liner is disposed, and the hole portion is a stepped hole whose diameter is reduced from the opening end toward the back side, so that the positional relationship between the cylinder liner and the rotary compression element is only the casing. Can be defined. For this reason, the shift | offset | difference which generate | occur | produces at the time of the assembly | attachment of a casing and an electric motor can be suppressed, and the substantially uniform performance with few individual differences can be exhibited. Furthermore, since the above-described casing can be formed with a single mold, it is possible to reduce the manufacturing cost by reducing the number of parts. Further, when the cylinder liner is disposed in the hole portion, the cylinder liner can be easily positioned by the end portion of the cylinder liner contacting the step portion of the stepped hole.

The diameter of the reduced diameter portion of the stepped hole may be larger than the inner diameter of the cylinder liner. According to this configuration, a side plate larger than the inner diameter of the cylinder liner can be disposed in the reduced diameter portion, and the opening of the cylinder liner can be easily blocked by the side plate.

  According to the present invention, the casing includes the cylinder liner on which the rotary compression element slides and the bearing portion that supports the rotation shaft of the motor, and is attached to the opening of the bottomed cylindrical motor case body. The positional relationship between the cylinder liner and the rotary compression element can be defined only by the casing. For this reason, the shift | offset | difference which generate | occur | produces at the time of the assembly | attachment of a casing and an electric motor can be suppressed, and the substantially uniform performance with few individual differences can be exhibited. Furthermore, since the above-described casing can be formed with a single mold, it is possible to reduce the manufacturing cost by reducing the number of parts.

It is a schematic diagram of a brake device using the vacuum pump concerning this embodiment. It is a horizontal fragmentary sectional view of a vacuum pump. It is the figure which looked at the vacuum pump from the back side. FIG. 3 is a partially enlarged view of FIG. 2.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments according to the invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram of a brake device 100 using a vacuum pump 1 according to an embodiment of the present invention as a negative pressure source. The brake device 100 includes, for example, front brakes 2A and 2B attached to left and right front wheels of a vehicle such as an automobile, and rear brakes 3A and 3B attached to left and right rear wheels. Each of these brakes is connected to each other by a master cylinder 4 and a brake pipe 9, and each brake is operated by a hydraulic pressure sent from the master cylinder 4 through the brake pipe 9.
The brake device 100 includes a brake booster (brake booster) 6 connected to the brake pedal 5, and the vacuum tank 7 and the vacuum pump 1 are connected in series to the brake booster 6 through an air pipe 8. It is connected. The brake booster 6 uses the negative pressure in the vacuum tank 7 to boost the pedaling force of the brake pedal 5, and it is sufficient to move the piston (not shown) of the master cylinder 4 with a small pedaling force. The brake force can be pulled out.
The vacuum pump 1 is disposed in the engine room of the vehicle, discharges the air in the vacuum tank 7 to the outside of the vehicle, and puts the vacuum tank 7 in a vacuum state. In addition, the use range of the vacuum pump 1 used for a motor vehicle etc. is -60kPa--80kPa, for example.

  FIG. 2 is a horizontal partial cross-sectional view of the vacuum pump 1, and FIG. 3 is a view of the vacuum pump 1 as seen from the rear side. However, FIG. 3 illustrates a state in which members such as the pump cover 24 and the side plate 26 are removed in order to show the configuration of the cylinder chamber S. In the following description, for convenience of explanation, the directions indicated by the arrows at the top of FIGS. 2 and 3 indicate the top, bottom, front, back, left and right of the vacuum pump 1. The front-rear direction is also referred to as the axial direction, and the left-right direction is also referred to as the width direction.

  As shown in FIG. 2, the vacuum pump 1 includes an electric motor 10 and a pump body 20 that operates using the electric motor 10 as a drive source, and the electric motor 10 and the pump body 20 are integrally connected. It is fixedly supported by a car body such as an automobile.

The electric motor 10 has an output shaft (rotating shaft) 12 extending from the approximate center of one end (rear end) of the motor case body 11 formed in a substantially cylindrical shape toward the pump body 20 side (rear side). doing. The output shaft 12 functions as a drive shaft that drives the pump main body 20, and rotates with reference to a rotation center X1 extending in the front-rear direction. A male screw that is screwed into a screw hole provided in the rotor 27 of the pump main body 20 is formed at the distal end portion 12A of the output shaft 12, and the output shaft 12 and the rotor 27 are rotatably coupled together. Furthermore, in this embodiment, the nut 70 is engaged with the male screw of the output shaft 12 at the front end side of the rotor 27, so that the movement of the rotor 27 toward the front end side of the output shaft 12 is restricted.
In the electric motor 10, when the power source (not shown) is turned on, the output shaft 12 rotates in the direction indicated by the arrow R (counterclockwise) in FIG. 3, thereby rotating the rotor 27 in the same direction around the rotation center X1 ( It is designed to rotate in the direction of arrow R).

  The motor case main body 11 is formed in a bottomed cylindrical shape having an opening 11 </ b> A at one end, and the opening 11 </ b> A side is fixed to the pump main body 20. Specifically, the motor case main body 11 includes a flange portion 11B integrally formed by bending the periphery of the opening portion 11A outward, and the flange portion 11B is fixed to the pump main body 20 with a screw 60.

  On the other hand, as shown in FIG. 2, the pump body 20 includes a casing body 22 attached to a flange portion 11 </ b> B formed on the rear side of the motor case body 11 of the electric motor 10, and a cylinder that is press-fitted into the casing body 22. A cylinder liner 23 that forms the chamber S and a pump cover 24 that covers the casing body 22 from the rear side are provided. In the present embodiment, a casing body 22, a cylinder liner 23, and a pump cover 24 are provided to constitute a casing 31 of the vacuum pump 1.

  The casing body 22 is made of, for example, a metal material having high thermal conductivity such as aluminum, and as shown in FIG. 3, the shape viewed from the rear side is substantially long in the vertical direction with the rotation center X1 as the center. It is formed in a rectangle. A communication hole 22A communicating with the cylinder chamber S provided in the casing main body 22 is formed on one side surface (right side surface) of the casing main body 22, and a vacuum suction nipple 30 is press-fitted into the communication hole 22A. ing. 2, the vacuum suction nipple 30 is a straight pipe extending outward in the width direction, and one end 30A of the vacuum suction nipple 30 is connected to an external device (for example, the vacuum tank 7 (see FIG. 1)). A tube or tube for supplying negative pressure air is connected.

The casing main body 22 is formed with a hole 72 that extends from the rear end (opening end) to the middle on the basis of the axial center X2 extending in the front-rear direction, and the cylinder liner 23 that is formed into a cylindrical shape in the hole 72. Is press-fitted. Of course, the cylinder liner 23 may be fitted into the hole 72 instead of being press-fitted.
The shaft center X2 is parallel to the rotation center X1 of the output shaft 12 of the electric motor 10 described above and, as shown in FIG. In this configuration, the shaft center X2 is eccentric so that the outer peripheral surface 27B of the rotor 27 centered on the rotation center X1 is in contact with the inner peripheral surface 23A of the cylinder liner 23 formed with the shaft center X2 as a reference.

The cylinder liner 23 is made of the same metal material as the rotor 27 (in this embodiment, iron). In this configuration, the cylinder liner 23 and the rotor 27 have the same thermal expansion coefficient. Therefore, regardless of the temperature changes of the cylinder liner 23 and the rotor 27, the outer peripheral surface 27B of the rotor 27 and the cylinder liner 23 when the rotor 27 rotates. The contact with the inner peripheral surface 23A can be prevented. The cylinder liner 23 and the rotor 27 may be made of different materials as long as they are metal materials having substantially the same thermal expansion coefficient.
Further, the cylinder liner 23 can be accommodated within the longitudinal range of the casing body 22 by press-fitting the cylinder liner 23 into the hole 72 formed in the casing body 22. Projection from the casing body 22 is prevented, and the casing body 22 can be downsized.
Further, the casing body 22 is formed of a material having higher thermal conductivity than the rotor 27. According to this, heat generated when the rotor 27 and the vane 28 are rotationally driven can be quickly transmitted to the casing body 22, so that the casing body 22 can sufficiently dissipate heat.

  The cylinder liner 23 is formed with an air supply port 23B that connects the communication hole 22A of the casing body 22 and the inside of the cylinder chamber S, and the air through the vacuum suction nipple 30 is communicated with the communication hole 22A and the air supply port 23B. Through the cylinder chamber S. In addition, air compressed in the cylinder chamber S through the casing body 22 and the cylinder liner 23 is discharged to the other side surface (left side surface) of the casing body 22 and the cylinder liner 23. Discharge ports 22C and 23C are provided. The discharge ports 22C and 23C are formed coaxially with the communication hole 22A and the air supply port 23B described above.

Side plates 25 and 26 for closing the opening of the cylinder chamber S are disposed at the front end and the rear end of the cylinder liner 23, respectively. The side plates 25 and 26 are set to have a diameter larger than the inner diameter of the inner peripheral surface 23A of the cylinder liner 23, and are urged by the seal rings 25A and 26A, respectively, to the front end and the rear end of the cylinder liner 23, respectively. It is pressed. Thus, a sealed cylinder chamber S is formed inside the cylinder liner 23 except for the air supply port 23B and the discharge ports 23C and 22C connected to the vacuum suction nipple 30.
In the present embodiment, the side plate 26 on the electric motor 10 side is disposed at the end of the hole 72 described above, and is sandwiched between the wall 72A of the hole 72 and the cylinder liner 23 via the seal ring 26A. ing.

  A rotor 27 is disposed in the cylinder chamber S. The rotor 27 has a cylindrical shape extending along the rotation center X1 of the electric motor 10, has a shaft hole 27A into which the output shaft 12 that is a drive shaft of the pump body 20 is screwed, and has a diameter from the shaft hole 27A. A plurality of guide grooves 27C are provided at equidistant intervals around the shaft hole 27A at intervals in the circumferential direction at positions separated in the direction. Further, as shown in FIG. 2, a concave portion 27H is formed on an end surface (so-called rear end surface) 27G of the rotor 27 facing the pump cover 24, and a nut 70 is formed on the male screw of the output shaft 12 in the concave portion 27H. Are screwed together. In the present embodiment, the length of the shaft end of the output shaft 12 extending into the recess 27H and the thickness of the nut 70 are set to be substantially the same as or slightly smaller than the depth of the recess 27H. The output shaft 12 and the nut 70 do not protrude from the end face 27G.

The length of the rotor 27 in the front-rear direction is set to be approximately equal to the length of the cylinder chamber S of the cylinder liner 23, that is, the distance between the inner surfaces of the two side plates 25 and 26 facing each other. And the side plates 25 and 26 are substantially closed.
Further, as shown in FIG. 3, the outer diameter of the rotor 27 is such that the outer peripheral surface 27B of the rotor 27 maintains a minute clearance with the portion of the inner peripheral surface 23A of the cylinder liner 23 located obliquely below the left side. Is set. Thereby, as shown in FIG. 3, a crescent-shaped space is formed between the outer peripheral surface 27 </ b> B of the rotor 27 and the inner peripheral surface 23 </ b> A of the cylinder liner 23.

  The rotor 27 is provided with a plurality (five in this example) of vanes 28 that divide a crescent-shaped space. The vane 28 is formed in a plate shape, and its length in the front-rear direction is set to be approximately equal to the distance between the mutually facing inner surfaces of the two side plates 25, 26, similar to the rotor 27. ing. These vanes 28 are arranged so as to be able to protrude and retract from guide grooves 27 </ b> C provided in the rotor 27. Each vane 28 protrudes outward along the guide groove 27 </ b> C by centrifugal force as the rotor 27 rotates, and a tip of the vane 28 comes into contact with the inner peripheral surface 23 </ b> A of the cylinder liner 23. As a result, the crescent-shaped space described above is divided into five compression chambers P surrounded by the two adjacent vanes 28, 28, the outer peripheral surface 27B of the rotor 27, and the inner peripheral surface 23A of the cylinder liner 23. Partitioned. These compression chambers P rotate in the same direction as the rotation of the output shaft 12 in the direction of arrow R of the rotor 27, and the volume of the compression chamber P increases in the vicinity of the air supply port 23B, while decreases in the discharge port 23C. . That is, the air sucked into the one compression chamber P from the air supply port 23B by the rotation of the rotor 27 and the vane 28 is compressed while being rotated along with the rotation of the rotor 27, and is discharged from the discharge port 23C.

  An exhaust portion 32 is attached to the left side surface of the casing body 22 where the discharge port 22C is formed so as to surround the discharge port 22C. The exhaust portion 32 includes a bulging portion 32A having a substantially center bulging outward in the width direction, and a peripheral portion 32B provided around the bulging portion 32A and closely contacting the left side surface of the casing body 22. The peripheral edge portion 32 </ b> B is attached to the casing body 22 with a screw 64. The bulging portion 32A is provided with an exhaust port 32C for discharging the air discharged from the discharge port 23C to the outside of the machine (outside of the vacuum pump 1). The exhaust port 32C is connected to the pump from outside the machine. A check valve 29 for preventing the backflow of air is attached.

  The pump cover 24 is disposed on the front side plate 26 via a seal ring 26 </ b> A, and is fixed to the casing body 22 with bolts 66. As shown in FIG. 2, a seal groove 22D is formed on the rear end surface of the casing body 22 so as to surround the cylinder liner 23, and an annular seal material 67 is disposed in the seal groove 22D.

  As described above, the vacuum pump 1 is configured by connecting the electric motor 10 and the pump main body 20, and the rotor 27 and the vane 28 connected to the output shaft 12 of the electric motor 10 include the cylinder liner of the pump main body 20. 23 slides in. For this reason, it is important to assemble the pump body 20 in accordance with the rotation center X1 of the output shaft 12 of the electric motor 10.

In the present embodiment, the casing main body 22 has a through hole 73 through which the output shaft 12 passes, and an annular bearing holding portion 74 around the through hole 73 at the approximate center of the surface to which the electric motor 10 is attached. The outer ring of the bearing (bearing part) 75 that supports the output shaft 12 is held on the inner peripheral surface 74A of the bearing holding part 74. The through hole 73 and the bearing holding portion 74 are formed around the rotation center X1, and are formed in the casing body 22 integrally with the hole portion 72 into which the cylinder liner 23 is press-fitted. According to this, when the cylinder liner 23 and the bearing 75 are provided in the hole portion 72 and the bearing holding portion 74 of the casing body 22, respectively, the bearing 75 and the shaft with the rotation center X1 as a reference are provided inside the casing body 22. Since the positional relationship with the cylinder liner 23 with respect to the center X2 can be defined, it is possible to suppress the deviation that occurs when the motor case main body 11 of the electric motor 10 is assembled to the casing main body 22, and the assembly The obtained vacuum pump 1 can exhibit substantially uniform performance with little individual difference.
Furthermore, since the casing body 22 can be formed using a single mold, it is possible to reduce the manufacturing cost by reducing the number of parts.

FIG. 4 is a partially enlarged view of FIG.
As described above, the cylinder liner 23 is press-fitted into the hole 72 formed in the casing body 22. In this configuration, the hole 72 is formed as a stepped hole having a diameter reduced from the rear end (opening end) of the casing body 22 toward the back side (wall portion 72A), and a liner holding portion in which the cylinder liner 23 is held. 72B, a diameter-reduced portion 72C that is smaller than the liner holding portion 72B and on which the side plate 26 is disposed, and a stepped portion 72D that is formed between the liner holding portion 72B and the reduced-diameter portion 72C. .
Accordingly, the cylinder liner 23 can be press-fitted until the cylinder liner 23 comes into contact with the stepped portion 72D, so that the press-fitting work of the cylinder liner 3 can be performed easily and accurately.
Further, since the hole diameter of the reduced diameter portion 72C is formed larger than the inner diameter of the cylinder liner 23, the side plate 26 larger than the inner diameter of the cylinder liner 23 can be disposed in the reduced diameter portion 72C. The opening of the cylinder liner 23 can be easily closed by the side plate 26.

  Although the best embodiment for carrying out the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications and changes can be made based on the technical idea of the present invention. It is.

1 Vacuum pump 6 Brake booster (brake booster)
7 Vacuum tank 10 Electric motor (motor)
11 Motor case 11A Opening 12 Output shaft (rotating shaft)
22 Casing body 23 Cylinder liner 27 Rotor (rotary compression element)
28 Vane (Rotary compression element)
31 Casing 72 Hole 72C Reduced diameter portion 74 Bearing holding portion 75 Bearing (bearing portion)
100 Brake device

Claims (2)

In a vacuum pump provided with a rotary compression element driven by a motor in a casing,
The casing includes a cylinder liner in which the rotary compression element to slide, and a bearing portion for supporting the rotation shaft of the motor, mounted et is the opening of the bottomed cylindrical motor case body,
The said casing is provided with the hole part by which the said cylinder liner is arrange | positioned, This hole part is a stepped hole diameter-reduced toward an inner side from an opening end, The vacuum pump characterized by the above-mentioned. 2. The vacuum pump according to claim 1, wherein a hole diameter of the reduced diameter portion of the stepped hole is formed larger than an inner diameter of the cylinder liner.

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