JP2870982B2 - Pump device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a pump device for supplying a pressure fluid to a power steering device or the like.

<Prior Art> In a conventional pump device, a configuration as shown in FIG. 3 for supporting a rotary shaft on a pump housing is known. In FIG. 3, a rotating shaft 51 to which a rotor 52 is connected at one end is rotatably supported by a ball bearing 54 and a guide bush 55 on a housing 53. The bearing portion is arranged such that a ball bearing 54 is provided at a position close to a pulley mounting portion 56 at the other end.
Thus, the rotary shaft 51 is axially positioned by the large-diameter portion 59 and the retaining ring 60. An oil seal 58 is disposed at the back of the oil seal 58, and is supported by a guide bush 55 at a position near the rotor 52.

With such an arrangement, a radial force applied to the pulley mounting portion 56 can be effectively received by the ball bearing 54, and the installation of the oil seal 58 enables
Foreign matter such as muddy water and dust is prevented from entering the housing 53 from outside.

<Problems to be Solved by the Invention> With the above configuration, the ball bearing 54 is disposed outside the oil seal 58 that prevents foreign matter such as muddy water from entering from outside.
Muddy water will be directly applied from outside. for that reason,
As the ball bearing 54, a so-called ZZ type in which shield plates are attached to both sides of a ball sliding portion is used. However, even if this ZZ type ball bearing is used, entry of foreign matter cannot be completely prevented. There is a problem of lowering.

In order to prevent foreign matter from entering the ball bearing 54, an oil seal 58 may be disposed on the open end side of the ball bearing 54. Since the distance between the support portions is increased and the moment due to the radial force applied to the pulley mounting portion 56 is increased, there is a problem that the life of the ball bearing 54 is shortened.

<Means for Solving the Problems> The present invention has been made to solve the above problems, and has a housing having a cylindrical hole, a rotating shaft inserted into the cylindrical hole of the housing, and a rotating shaft. A rotor connected to one end of the housing and rotating within the housing; a cam ring disposed to surround the rotor; and a cam ring disposed within the cylindrical hole and rotatably bearing the rotary shaft with respect to the housing. A ball bearing having shield plates mounted on both sides of a ball sliding portion, and the ball bearing fixed to the housing on the opening side of the cylindrical hole of the ball bearing so that the ball bearing is axially movable with respect to the housing. In a pump device having a positioning member for positioning, a thin-film synthetic resin sealing portion is provided between the ball bearing and the positioning member. A material is installed, and an outer peripheral portion of the seal member is fitted in a liquid-tight manner between the outer race of the ball bearing and the positioning member.

<Operation> A ball bearing having a shield plate attached to both sides of the ball sliding portion is used, and a thin-film synthetic resin sealing member is provided between the ball bearing and the positioning member. This prevents muddy water, dust and the like from entering the ball sliding portion of the ball bearing even when dust and the like are applied.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. Reference numeral 10 denotes a rear housing of the pump. A hollow chamber 11 having a bottom is formed in the rear housing 10, and the hollow chamber 11 is open at one end surface of the rear housing 10. A circumferential hole 13 is provided in the front housing 12 for closing the opening of the hollow chamber 11.
The rotary shaft 14 is inserted through the circumferential hole 13. The rotating shaft 14 is rotatably mounted on the front housing 12 by a ball bearing 15 and a guide bush 16 as described later.

The hollow chamber 11 houses a cam ring 17 having one end face in contact with the front housing 12, a side plate 18 in contact with the other side of the cam ring 17, and a pressing plate 19 in contact with the other side of the side plate 18. A spring 20 is compressed and inserted between the pressing plate 19 and the rear housing 10. A cam surface 21 is formed on the inner periphery of the cam ring 17, and a rotor 23 that slidably holds the plurality of vanes 22 slidably contacting the cam surface 21 in the radial direction.
Are housed in the cam ring 17. This rotor 23
Is spline-engaged with one end of the rotating shaft 14.

Further, one side surface of the vane 22 and the rotor 23 is in sliding contact with the side surface of the front housing 12, and the other side surface is in sliding contact with the side surface of the side plate 18, and a sealing action is performed at each sliding contact surface. As a result, a plurality of pump chambers are formed by the vanes 22 between the cam surface 21 of the cam ring 17 and the rotor 23, and the volume of each pump chamber is changed by the rotation of the rotor 23. As shown in FIG. 2, suction ports 24 and 25 are formed in the front housing 12 and the side plate 18 corresponding to the pump chamber performing the expansion stroke. Discharge ports 26 and 27 are formed in the housing 12 and the side plate 18. These suction ports 24 and 25 communicate with a bypass passage 29 via an annular passage 28 and a not-shown passage groove formed in the pressing plate 19. A fluid supply passage 30 opens in the bypass passage 29 at right angles to the bypass passage 29. One end of the fluid supply passage 30 is connected to a reservoir (not shown), and fluid is supplied from the reservoir. The discharge ports 26 and 27 are
The pressure chamber 32 communicates with the pressure chamber 32 through the through hole 31 and communicates with a discharge port (not shown) through a passage (not shown).

Further, a valve housing hole 33 is formed in the rear housing 10 in a direction orthogonal to the axis of the rotating shaft 14, and a valve member 34 of a flow control valve 38 is slidably fitted in the valve housing hole 33, At both ends of the valve member 34, valve chambers 36 and 37 are formed. Also,
A spring 35 for pressing the valve member 34 is provided in the valve chamber 36, and the valve chamber 37 is connected to the pressure chamber 32 via a conduction path 39.

The rotating shaft 14 has a pulley mounting portion 40 at one end of which a pulley (not shown) is fixed, and is rotatably supported on the front housing 12 at two locations: a ball bearing 15 and a guide bush 16. I have. The arrangement of the bearing is such that the ball bearing 15 is provided at a position close to the pulley mounting portion 40, the oil seal 44 is provided at the back thereof, and the guide bush 16 is provided at a position close to the rotor 23. .
With this arrangement, the ball bearing 15 can effectively receive the radial force applied to the pulley mounting portion 40.

The ball bearing 15 is fitted and fixed in a large-diameter hole 41 formed in the front housing 12, and the other end, which is the opening end of the through hole 13, is fixed by a snap ring 43. In addition, the ball bearing 15 abuts on the stop ring 42 at one end and the large-diameter portion 14a provided on the rotary shaft 14 with respect to the rotary shaft 14, thereby positioning the rotary shaft 14 in the axial direction. . The ball bearing 15 uses a so-called ZZ type in which shield plates are attached to both sides of the ball sliding portion, and care is taken to prevent foreign matters such as muddy water and dust from entering the ball sliding portion.

Further, a thin-film sealing member 45 is provided between the ball bearing 15 and the snap ring 43. The seal member 45 is made of a synthetic resin such as tetrafluoroethylene resin (Teflon), and has a circular shape and a circular hole through which the rotating shaft 14 penetrates at the center. The outer peripheral portion of the sealing member 45
The outer ring of the ball bearing 15 and the snap ring 43 are fitted in a liquid-tight manner. Further, the end of the circular hole is assembled so as to be deformed toward the snap ring 43 so as not to slide on the inner ring side of the ball bearing 15, so that friction caused by sliding contact with the inner ring side is reduced.

The operation of the above-described pump device will be described. When a rotational force is applied to a pulley (not shown), the rotary shaft 14 is driven to rotate via the pulley mounting portion 40. Thereby, the fluid is sucked into the pump chamber from the suction ports 24 and 25 from the reservoir (not shown) via the fluid supply passage 30, the bypass passage 29, the passage groove, and the annular passage. The fluid pressurized by the pump action flows from the discharge ports 26 and 27 through the through holes 31 to the pressure chamber 32.
And presses the pressing plate 19, and is sent out from the discharge port to the power steering device or the like via the passage. Also, when the discharge flow rate increases, the flow rate flowing into the valve chamber 37 via the conduction path 39 increases, so that the valve member 34 moves against the pressing force of the spring 35, and the excess flow is bypassed to the bypass passage 29.

The present invention relates to a rotary shaft 14 of a pump device that operates as described above.
In the ball bearing 15, a so-called ZZ type in which shield plates are mounted on both sides of a ball sliding portion is used, and a thin-film sealing member 45 made of synthetic resin is further used.
With this configuration, it is possible to improve the sealing performance with a configuration in which the sliding resistance is small, without requiring any additional processing on the housing of the current pump device.

In the above embodiment, the seal member 45 is snap-ringed.
Although it is fixed by 43, it is not limited to this structure, but can be applied to a structure fixed by a nut or the like, for example.

<Effect of the Invention> As described above, the present invention uses a ball bearing in which shield plates are attached to both sides of a ball sliding portion as a ball bearing for bearing the rotation shaft of the pump device.
By installing a thin-film synthetic resin sealing member between the ball bearing and a positioning member for positioning the ball bearing in the axial direction with respect to the housing, in addition to the shield plate attached to the ball bearing, Since the sealing member exhibits the sealing performance, the sealing performance can be remarkably improved. Also, since the seal member is assembled by being fitted in a liquid-tight manner between the outer ring of the ball bearing and the positioning member,
No additional work is required on the housing of the current pump device.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of the pump device of the present invention, and FIG.
FIG. 1 is a cross-sectional view taken along line II-II in FIG. 1, and FIG. 3 is a cross-sectional view of a main part of a conventional pump device. 11 ... rear housing, 12 ... front housing, 13
…… Cylindrical bore, 14… Rotary shaft, 15 …… Ball bearing,
17 ... cam ring, 23 ... rotor, 43 ... positioning member (snap ring), 45 ... seal member.

Claims (1)

(57) [Claims] 1. A housing having a cylindrical hole formed therein, a rotating shaft inserted into the cylindrical hole of the housing, a rotor connected to one end of the rotating shaft and rotating within the housing, and a rotor surrounding the rotor. And a cam ring arranged in
A ball bearing disposed in the cylindrical hole so as to rotatably support the rotating shaft with respect to the housing, and having shield plates attached to both sides of a ball sliding portion; and the cylinder of the ball bearing. In a pump device having a positioning member fixed to the housing on the opening side in a hole and positioning the ball bearing in the axial direction with respect to the housing, a thin film composite between the ball bearing and the positioning member is provided. A pump device comprising a resin-made sealing member, and an outer peripheral portion of the sealing member fitted in a liquid-tight manner between an outer ring of the ball bearing and the positioning member.