JPH0849646A - Liquid-pressure pump - Google Patents

Abstract

PURPOSE:To restrain generation of abrasion on a pressurecontact part of a cam ring with a regulating means by elastically receiving the load to be generated when the cam ring is moved in the axial direction by a regulating means, and regulating the movement, in a liquid-pressure pump to be used for a liquid pressure controller for controlling traction. CONSTITUTION:A cam ring 17 assembled to an eccentric shaft part 11a through a needle roller 16 is eccentrically rotated by the rotation of a driving shaft 11, and a pair of plungers 25, 26 so arranged as to be faced to each other while pinching the cam ring 17 in the radial direction of the driving shaft 11 are reciprocated. Fluid of brake fluid sucked into pump chambers R1, R4 is boosted by the movement of respective plungers 25, 26 and discharged to discharging chambers R3, R6. In this case, spring steel-made flat washers 21, 22 as a regulating means for regulating the axial movement of the cam ring 17 are assembled on the ends of respective axial directions of the cam rings 17 and between bearings 12, 13 through balance washers 23, 24, thereby the smooth operation of the pump is secured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention controls the locking of all wheels during braking (antilock control) and controls the slip of driving wheels during traction (traction control), for example, in an automobile braking system. The present invention relates to a hydraulic pump used in a hydraulic control device.

[0002]

2. Description of the Related Art As one of hydraulic pumps, a cam ring is rotatably and axially movably mounted on an eccentric shaft portion provided on a drive shaft via a needle roller, and is also arranged in a radial direction of the drive shaft. A pair of plungers are arranged so as to face each other with the cam ring sandwiched therebetween, and each plunger is spring-biased toward the cam ring in a state of being assembled to a cylinder via a seal ring, and each of the plungers is rotated by the rotation of the drive shaft. There is one in which a plunger reciprocates in the radial direction of the drive shaft, which is disclosed in, for example, Japanese Patent Laid-Open No. 1-167469.

[0003]

In the hydraulic pump of the above-mentioned publication, the cam ring is held by a pair of thrust rings provided on the drive shaft and its axial movement is restricted. By the way, in the above-mentioned hydraulic pump, when the accuracy of parts is within the allowable range but the axis parallelism between the drive shaft and the eccentric shaft part is poor, for example, one plunger is rotated by the rotation of the drive shaft. When the pump action is obtained and the other plunger does not provide the pump action, the cam ring may be pushed in one axial direction and press contact with one thrust ring, resulting in significant wear at the press contact part. is there.

One example of the above-mentioned mechanism of wear generation (example in which the desired pumping action is obtained by the plunger above the drawing)
Will be described with reference to the schematic explanatory views of FIGS. The state of FIG. 2 (the cam ring 2 is at an intermediate point where the top dead center is changed to the bottom dead center, and the pump chambers Ra and Rb are
Pressure is substantially zero), the axes of the drive shaft 1 and the eccentric shaft portion 1a are parallel to each other, the cam ring 2 is orthogonal to the axial lines of the plungers 3a and 3b, and the plungers 3a and 3b are each seal ring. Each cylinder 5a, 5b by 4a, 4b
The springs 6a and 6b are urged toward the cam ring 2 with the same load F1 = F2 while being held in the approximate center, and there is a gap a between the plungers 3a and 3b and the cylinders 5a and 5b. There is a gap b between the cam ring 2 and the thrust ring 7 on the left side in the drawing. In the state of shifting from FIG. 2 to FIG. 3 (the state in which the cam ring 2 shifts to the bottom dead center and the pressures of the pump chambers Ra and Rb are substantially zero), the drive shaft 1
On the other hand, since the shaft of the eccentric shaft portion 1a tilts downward to the left, the cam ring 2 also tilts downward to the left, and the load F2 of the spring 6b becomes larger than the load F1 of the spring 6a. Only s is pushed, and the gap between the cam ring 2 and the thrust ring 7 on the left side in the drawing becomes bs. A state in which the state moves from FIG. 3 to FIG. 4 and then to FIG. 5 (a state in which the cam ring 2 moves upward from the bottom dead center, the pressure in the lower pump chamber Rb is substantially zero, and the pressure in the upper pump chamber Ra increases. ), When the shaft of the eccentric shaft portion 1a is tilted downward to the left with respect to the drive shaft 1, the pressure in the upper pump chamber Ra causes the plunger 3a to tilt to the right in the drawing until it contacts the cylinder 5a. The cam ring 2 is pushed to the right by a in the figure, and the gap between the cam ring 2 and the thrust ring 7 on the left in the figure becomes b−s + a. In the state of FIG. 5 (the state in which the cam ring 2 is at the middle point where the bottom dead center changes to the top dead center, the pressure in the lower pump chamber Rb is substantially zero, and the pressure in the upper pump chamber Ra increases), Since the axis of the eccentric shaft portion 1a is parallel to the drive shaft 1, each seal ring 4
The plungers 3a and 3b are returned to substantially the center of the cylinders 5a and 5b by the restoring force of the cam rings 2a and 4b.
And the gap between the thrust ring 7 on the left side of the drawing is bs + a-
a = b−s. The state of FIG. 6 (the state in which the cam ring 2 moves from the intermediate point to the top dead center, the pressure in the lower pump chamber Rb is substantially zero, and the pressure in the upper pump chamber Ra increases)
Then, the shaft of the eccentric shaft portion 1a is tilted downward to the right with respect to the drive shaft 1, and the cam ring 2 is tilted leftward in the drawing until the plunger 3a comes into contact with the cylinder 5a by the pressure of the upper pump chamber Ra. Only a is pushed to the left, and the gap between the cam ring 2 and the thrust ring 7 on the left side in the drawing is bs.
-A. The state of FIG. 7 (the state in which the cam ring 2 moves to the top dead center and the pressures of the pump chambers Ra and Rb are substantially zero)
Then, although the upper plunger 3a is returned to substantially the center of the cylinder 5a by the restoring force of the upper seal ring 4a, the load F1 of the spring 6a becomes larger than the load F2 of the spring 6b, and the cam ring 2 is illustrated by the spring load difference. It is pushed to the left by s, and the gap between the cam ring 2 and the thrust ring 7 on the left side in the figure becomes b−s−a + a−s = b−2s. In the state of FIG. 8 (the state in which the cam ring 2 is at the middle point where the top dead center is changed to the bottom dead center and the pressures in the pump chambers Ra and Rb are substantially zero), the restoring force of the upper seal ring 4a causes the upward movement. The plunger 3a is returned to substantially the center of the cylinder 5a, and the gap between the cam ring 2 and the thrust ring 7 on the left side in the drawing becomes b-2s + s = bs. Therefore, in such a liquid pump, the gap between the cam ring 2 and the thrust ring 7 on the left side in the drawing is reduced by s for each rotation, and the load acting in the state of FIG. In addition to the thrust ring 7 on the left side, wear occurs at the press contact portion between the cam ring 2 and the thrust ring 7 on the left side in the drawing.

[0005]

In order to solve the above-mentioned problems, in the present invention, a cam ring is attached to an eccentric shaft portion provided on a drive shaft via a needle roller so as to be movable in the axial direction. A pair of plungers are arranged to face each other across the cam ring in the radial direction of the drive shaft, and each plunger is spring-biased toward the cam ring in a state of being assembled to the cylinder via a seal ring,
In the hydraulic pump, wherein each of the plungers reciprocates in the radial direction of the drive shaft by the rotation of the drive shaft,
Each axial end portion of the cam ring is provided with a regulation means for elastically receiving and regulating the axial movement of the cam ring. It is desirable that each restricting means be composed of a flat washer made of a spring material and assembled on the drive shaft.

[0006]

In the hydraulic pump according to the present invention, the load when the cam ring is moved in the axial direction can be elastically received by the restricting means to restrict the axial movement of the cam ring. It is possible to suppress the occurrence of wear at the pressure contact portion between the cam ring and the regulating means, and improve the durability of the hydraulic pump. Further, when the regulating means is constituted by a flat washer made of a spring material assembled on the drive shaft, the hydraulic pump can be made compact.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. The hydraulic pump P shown in FIG. 1 controls the locking of all the wheels during braking (anti-lock control) and the slip of the driving wheels during driving (traction control) in a vehicle brake device. It is an electric hydraulic pump used for the control device,
Drive shaft 11 driven by an electric motor (not shown)
Has an eccentric shaft portion 11a and is rotatably assembled to the pump housing 14 via a pair of ball bearings 12 and 13 on both sides of the eccentric shaft portion 11a. A cam ring 17 is mounted rotatably and axially movable via a large number of needle rollers 16 held by. Also, drive shaft 1
Spring steel flat washers 21 and 22 are mounted on both sides of the eccentric shaft portion 11a as a restricting means for elastically receiving and restricting the axial movement of the cam ring 17, and the rotational balance of the drive shaft 11 is adjusted. And a balance washer 23 for sandwiching the flat washers 21, 22 with the eccentric shaft portion 11a of the drive shaft 11 while ensuring the flexibility of the flat washers 21, 22 (deflection associated with the axial movement of the cam ring 17). 24 are assembled respectively.

A pair of plungers 25 and 26 and a pair of cylinders 27 and 28 are attached to the pump housing 14 with the cam ring 17 interposed therebetween in the radial direction of the drive shaft 11. The plunger 25 is assembled to the cylinder 27 through a seal ring 31 so as to be liquid-tight and slidable in the cylinder axial direction to form a pump chamber R1 in the cylinder 27, and a spring provided between the plunger 25 and the cylinder 27. It is urged toward the cam ring 17 by 32, and the pump chamber R
Reference numeral 1 denotes a suction check valve V1 assembled to the plunger 25, a communication passage 25a provided to the plunger 25 and a communication passage 27a provided to the cylinder 27 to communicate with the suction chamber R2 and a discharge check valve V2 assembled to the cylinder 27. Through the discharge chamber R3. The cylinder 27 is liquid-tightly assembled to the pump housing 14 via the seal rings 33 and 34, and is elastically fixed by a spring 36 (having a spring force larger than the spring 32) provided between the cylinder 27 and the plug 35. . The plug 35 is liquid-tightly assembled to the pump housing 14 via a seal ring 37, and is fixed by a clip 38 provided between the pump housings 14 so as not to come off.

On the other hand, the plunger 26 has a seal ring 4
1 is installed in the cylinder 28 in a liquid-tight manner so as to be slidable in the cylinder axial direction.
And a spring 42 provided between the cylinder 28 and
The pump chamber R4 is urged toward the cam ring 17 (has substantially the same spring force as the spring 32), and the pump chamber R4 is attached to the plunger 26 by an intake check valve V3 (the opening pressure of the intake check valve V1 is different from that of the intake check valve V1). Is large) and the plunger 26
Communication passage 26a provided in the cylinder and communication passage 2 provided in the cylinder 28
8a communicates with the suction chamber R5 and the cylinder 2
Discharge check valve V4 (Discharge check valve V2
Of the discharge chamber R6)
Is in communication with. The cylinder 28 includes a seal ring 43,
It is liquid-tightly assembled to the pump housing 14 via 44 and is elastically fixed by a spring 46 (having a spring force larger than that of the spring 42 and substantially the same as that of the spring 36) provided between the pump housing 14 and the pump housing 14. The plug 45 is liquid-tightly assembled to the pump housing 14 via a seal ring 47, and is fixed by a clip 48 provided between the pump housings 14 so as not to come off.

In the hydraulic pump P of the present embodiment constructed as described above, rotation of the drive shaft 11 allows both plungers 25 and 26 to achieve desired pumping action (in antilock control mode). Operation), there is a use state (operation during traction control) in which the desired pump action is obtained by one plunger 25 and the pump action is not obtained by the other plunger 26. Even if the cam ring 17 is pushed in one axial direction by the operation described in the generation mechanism, the load is elastically received from the cam ring 17 by the bending of the flat washer 21 or 22, and the axial direction of the cam ring 17 is received. Movement is regulated elastically. Therefore, it is possible to suppress the occurrence of wear at the pressure contact portion between the cam ring 17 and the flat washer 21 or 22, and improve the durability of the hydraulic pump P.

In the above embodiment, the spring steel flat washers 21, 22 are mounted on the drive shaft 11 with the regulating means for elastically receiving and regulating the axial movement of the cam ring 17.
The hydraulic pump is configured to be compact, but in place of the flat washers 21 and 22, thrust rings (which hardly bend) are respectively attached to the drive shaft at each axial end of the cam ring. It is also possible to form the regulating means by a spring that is interposed between each thrust ring and each balance washer 23, 24 to urge each thrust ring toward the cam ring.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a hydraulic pump according to the present invention.

FIG. 2 is a schematic explanatory view showing one step of a mechanism of occurrence of wear to be solved by the present invention.

FIG. 3 is a schematic explanatory view showing one step of a mechanism of wear generation to be solved by the present invention.

FIG. 4 is a schematic explanatory view showing one step of a mechanism of occurrence of wear to be solved by the present invention.

FIG. 5 is a schematic explanatory view showing one step of a mechanism of wear generation to be solved by the present invention.

FIG. 6 is a schematic explanatory view showing one step of a mechanism of wear generation to be solved by the present invention.

FIG. 7 is a schematic explanatory view showing one step of a mechanism of wear generation to be solved by the present invention.

FIG. 8 is a schematic explanatory view showing one step of a mechanism of wear generation to be solved by the present invention.

[Explanation of symbols]

11 ... Drive shaft, 11a ... Eccentric shaft part, 16 ... Needle roller, 17 ... Cam ring, 25, 26 ... Plunger, 2
7, 28 ... Cylinder, 31, 41 ... Seal ring, 3
2, 42 ... Spring, 21, 22 ... Flat washer, P ... Hydraulic pump.

Claims (2)

[Claims] 1. A cam ring is attached to an eccentric shaft portion provided on a drive shaft via a needle roller so as to be rotatable and axially movable, and a pair of cam rings are sandwiched in the radial direction of the drive shaft. Plungers are arranged to face each other, and each plunger is spring-biased toward the cam ring in a state of being assembled to the cylinder via a seal ring,
In the hydraulic pump, wherein each of the plungers reciprocates in the radial direction of the drive shaft by the rotation of the drive shaft,
A hydraulic pump, characterized in that each of the axial ends of the cam ring is provided with a regulating means for elastically receiving and regulating the axial movement of the cam ring. 2. The hydraulic pump according to claim 1, wherein the regulating means is constituted by a flat washer made of a spring material, which is assembled on the drive shaft.