JPH0596485U - In-tank fuel pump - Google Patents

Abstract

(57) [Summary] [Purpose] The objective is to obtain an in-tank fuel pump with improved pump efficiency and excellent durability. [Structure] A steel ball 18 which has been hardened and precision-finished is inserted into a bearing 11 by means of a clearance fit so as to be freely rotatable so as to support a thrust load generated on a lower end surface of a rotary shaft 16 when a pump is operated. [Effect] Since the steel ball 18 having a small contact area receives a thrust load generated on the lower end surface of the rotating shaft 16, sliding resistance is reduced, and wear and mechanical loss are extremely reduced.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an in-tank type fuel pump for supplying fuel to an engine of an automobile or the like.

[0002]

[Prior Art]

 FIG. 2 is a sectional view of a conventional general in-tank fuel pump. In the figure, a magnet 2 forming a magnetic circuit is fixed to a central portion of the inner surface of a cylindrical yoke 1. A cover-out 3 having a discharge port 3a and a self-aligning bearing 4 is press-fitted into an opening at one end of the yoke 1. A bracket 8 having a brush 5, a brush holder 6, a brush spring 7 and the like is attached to the opening at the other end of the yoke 1.

The impeller 9 having a plurality of blades 9 a on the outer periphery is rotatably attached between the bracket 8 and the pump cover 10. The pump cover 10 has a suction port 10a, and a bearing 11 and a contact plate 12 are attached to the center thereof. A is an armature that constitutes an electric motor and comprises a core 13, a coil 14, a commutator 15 and a rotary shaft 16. The two parts 15a provided on the end surface of the commutator 15 are engaged with the holes 9b of the impeller 9 to transmit the rotation. A lead wire 17 for supplying electric power from the outside is connected to the brush 5.

Next, the operation will be described. When a voltage is applied to the lead wire 17, an electric current flows through the brush 5, the commutator 15, and the coil 14, and the armature A rotates due to the magnetic action. Therefore, the driving force is transmitted to the impeller 9 via the one part 15a of the commutator 15 press-fitted into the rotating shaft 16, and the impeller 9 rotates. Then, a large number of blades 9a provided on the outer periphery of the impeller 9 generate a vortex flow to perform a pumping action, and the fuel is supplied from an intake port 10a installed opposite to a lower surface portion in a fuel tank (not shown). The fuel is sucked and supplied to the engine (not shown) through the discharge port 3a.

[0005]

[Problems to be solved by the device]

 In the conventional in-tank fuel pump configured as described above, the suction port 10a is normally installed vertically in the fuel tank because of its suction performance. Therefore, there is a problem in that a thrust load is applied to the lower end surface of the rotating shaft 16 and mechanical loss due to wear and friction increase occurs despite the provision of the hardened plate 12. Japanese Patent Laid-Open No. 63-277889 discloses a structure in which the end face of the rotating shaft is supported by a spherical thrust receiving member. However, since the thrust receiving member is fixed, the shaft center of the rotating shaft and the thrust receiving member are fixed. If the axis of the spherical part deviates, the friction reducing effect will decrease and the rotation will not be smooth. In addition, there is a problem that it is mechanically difficult to match the axes.

The present invention has been made to solve the above problems, and an object thereof is to obtain an in-tank fuel pump having high pump efficiency and excellent durability.

[0007]

[Means for Solving the Problems]

 The in-tank fuel pump according to the present invention has a steel ball rotatably inserted in the center of the bearing hole so that the lower end surface of the rotating shaft contacts.

[0008]

[Action]

 In this invention, since the lower end surface of the rotating shaft that receives the thrust load is supported by the spherical surface having a small contact area, the sliding resistance is reduced, and the mechanical loss and wear are extremely reduced. Moreover, since the steel ball is rotatable, the axis of the rotating shaft and the center of the steel ball necessarily coincide with each other due to the influence of sliding resistance.

[0009]

【Example】

 FIG. 1 is a sectional view of an in-tank fuel pump according to an embodiment of the present invention. The same or corresponding parts as those in FIG. 2 are designated by the same reference numerals and the description thereof will be omitted. In the figure, a spherical steel ball 18 whose material has been hardened and whose surface has been subjected to precision finishing is loosely fitted in the bearing hole 11a of the bearing 11 so as to be sandwiched between the lower end surface of the rotating shaft 16 and the contact plate 12. It is rotatably inserted.

In the in-tank fuel pump configured as described above, the lower end surface of the rotating shaft 16 that receives a thrust load as the electric motor rotates is pressed against the steel ball 18, but the contact surface area is very small. Reduces mechanical loss and wear. In addition, the curing treatment and precision finishing drastically reduce the contact resistance, resulting in very low mechanical loss and wear. Furthermore, since the steel ball 18 is rotatable, the rotation axis 16 rotates and the axial center of the rotation shaft 16 and the center of the steel ball 18 naturally coincide with each other due to the influence of sliding resistance. Therefore, the reduction of the friction reducing effect due to the displacement of the shaft center is also prevented.

[0011]

[Effect of the device]

 As described above, in the in-tank fuel pump of the present invention, the thrust load of the rotating shaft is received by the rotatable steel ball, so the contact resistance can be reduced and the shaft between the rotating shaft and the steel ball can be reduced. Misalignment can be prevented, and as a result, mechanical loss and wear can be reduced, and pump efficiency and durability can be improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an in-tank fuel pump according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view of an example of a conventional in-tank fuel pump.

[Explanation of symbols]

 9 Impeller 11a Bearing hole 16 Rotating shaft 18 Steel ball

Claims (1)

[Scope of utility model registration request] 1. An in-tank fuel pump having an impeller driven to rotate by an electric motor and serving as a pump,
An in-tank type fuel pump, wherein a rotatable steel ball is provided at the center of the bearing hole of the rotary shaft so as to support the thrust load generated on the lower end surface of the rotary shaft of the impeller.