JPH0735778U - Hydraulic pump - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a hydraulic pump that reduces the level of generated noise and reduces the device cost. [Structure] A piston 6a having a seal ring g mounted on a cylinder body 24a is slidably fitted, and a compression spring 8a arranged between the piston 6a and the closed end of the cylinder body
The cam ring A is biased to the left and is constantly in pressure contact with the outer peripheral portion of the cam ring A, and the center axis C of the cam ring A is fixed in alignment with the rotating shaft of the electric motor M. By driving the rotating shaft of the electric motor M, the cam ring A reciprocates the piston 6a three times in this one rotation. Thus the check valve from the liquid chamber H a 25a, 26
By alternately opening a, it is possible to supply the pressure liquid to the pipe line at a frequency three times higher than in the conventional case.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a hydraulic pump, and more particularly to an optimal hydraulic pump for use in an anti-skid brake device.

[0002]

[Prior art and its problems]

 At present, various anti-skid brake devices have been developed to prevent skidding of automobiles, and hydraulic pumps are used for all of them. These discharge the pressure fluid supplied to the wheel cylinders of the wheels to the low pressure reservoir in order to loosen the brake, then suck it in by the hydraulic pump and supply it to the pressure fluid supply line connected to the master cylinder side. , This discharge pressure is used in the case of reloading according to the command of the computer, but the current hydraulic pump rotates the eccentric cam having the central axis at the eccentric position with respect to the shaft of the motor. The piston in the cylinder is reciprocated to deliver the discharge pressure liquid to the pressure liquid supply line. However, since a so-called eccentric cam mechanism having an eccentric center axis with respect to the shaft of the motor is used, the cost is increased for this, and the driving of this hydraulic pump causes noise. It is required to suppress this as much as possible.

In the “pump” described in JP-A-1-195165, a diaper-shaped cam ring is shown, and the central shaft is connected to the wheel shaft, which rotates. Although it discloses that the hydraulic piston reciprocates due to this, in the figure showing the specific configuration, it is configured by a combination of a plunger, a piston, a bowl valve, etc. The pump is integrated, and the bowl valve is normally closed in the piston body of the pump, which is composed of the plunger and the piston integrated with the pump, and the anti-skid control is started. Switch the solenoid valve to drain the brake fluid from the wheel cylinder of the wheel to the reservoir, and then depress the brake pedal from the master cylinder. By doing so, the hydraulic pressure applied to the cut valve in the modulator overcomes the hydraulic pressure around the outer circumference of the piston (fluid pressure due to the pressure receiving area difference) communicating with the wheel cylinder, which raises the piston body, This causes the cam ring to come into contact with the upper cam ring, and since the cam ring is now rotating around the central axis, it reciprocates up and down with the piston in contact. As a result, the bowl valve arranged inside the piston body opens and closes. Therefore, the brake fluid on the reservoir side is simply sent to the wheel cylinder side, that is, because the solenoid valve connects the reservoir and the wheel cylinder to the reservoir and circulates. This hydraulic pressure is immediately transmitted to the wheel cylinder when the solenoid valve is switched to the closed position. However, when the brake fluid pressure from the master cylinder disappears, that is, when the depression force on the brake pedal is released, the piston body moves downward and the cam ring does not abut it, so the pump does not act. Due to such a structure and operation, it is integrated with the modulator as is clear from the figure, but the structure is complicated and it is usually separated from the piston body that abuts and drives when the hydraulic pump of the cam ring acts. Since it does not function as a pump until the contact, and it may be necessary to perform the suction function from the reservoir even when the pedal force is released from the brake pedal, the pump of the hydraulic pump There is no effect, and in some cases anti-skid control cannot be performed. Although the hydraulic pump described in the above publication has the above-mentioned drawbacks, its cost is high due to its more complicated structure.

[0004]

[Problems to be solved by the device]

 The present invention has been made in view of the above problems, and an object of the present invention is to provide a hydraulic pump that can appropriately perform anti-skid control to further reduce cost and noise.

[0005]

[Means for solving problems]

 The above object is to provide a cylinder body whose one end is closed, a piston which is slidable by mounting a seal ring in the cylinder body, and which is stretched between the piston and the closed end side of the cylinder. A spring for urging the cylinder body toward the opening end side of the cylinder body, an end portion of the piston on the opening end side of the cylinder body, a cam ring that always abuts at its outer peripheral portion by the spring force of the spring, and a center of the cam ring. An electric motor that rotationally drives the cam ring around the axis of the shaft, a liquid chamber defined between the piston and the closed end of the cylinder body, and a liquid chamber that communicates with the liquid chamber and is connected to the cylinder body. The cam ring has at least one through hole formed therein, and the cam ring has, on the outer peripheral portion thereof, two or more protruding portions that are equidistant from the axial center of the central axis at equal angular intervals. Hydraulic pump to symptoms, is accomplished by.

[0006]

[Action]

 Since the cam ring is fixed with its center axis aligned with the rotation axis of the electric motor that drives it, this manufacturing cost is lower than before, and the cam ring is equal to the outer periphery of the center axis of the center axis. Since two or more protrusions at the maximum distance are formed at equal angular intervals, when the shaft rotates 360 degrees around the axis, the reciprocating movement of the piston pressed against it depends on the number of protrusions. The dynamic frequency can be doubled as compared with the conventional one. Therefore, even if the same pressure liquid is supplied to the pressure liquid supply pipeline side, the rotation speed of the electric motor can be reduced. Therefore, noise can be reduced.

[0007]

【Example】

 Hereinafter, an anti-skid brake device using a hydraulic pump according to an embodiment of the present invention will be described with reference to the drawings.

1 to 3 show an anti-skid brake device according to an embodiment of the present invention. In FIG. 1, the booster portion of the master cylinder 1 with a booster, that is, the booster portion 3 has a brake pedal 2 provided therein. When the brake pedal 2 is depressed, a hydraulic pressure is generated in the two hydraulic pressure generating chambers in the cylinder body 4 by the assisting action of the booster unit. A reservoir 5 for integrally storing the brake working fluid is attached inside the cylinder body 4.

Pipe lines 7a and 7b are connected to both hydraulic pressure generating chambers of the cylinder body 4, and one pipe line 7a is connected to the right front wheel 15a and the left rear wheel through various members described later. The wheel cylinder of 16a is connected, and the wheel cylinders of the left front wheel 15b and the right rear wheel 16b are also connected to the other conduit 7b through similar members. That is, in this embodiment, the X pipe is adopted.

Since the same members are connected to the two systems with the same structure, only one system, that is, the member connected to the side of the pipeline 7 a will be described (note that the corresponding systems of other systems are the same). Structural members shall have the suffix b instead of the suffix a). Wheel cylinders of wheels 15a and 16a are connected to the pipeline 7a via supply valves 11a and 12a. These wheel cylinders are connected to the discharge valves 13a and 14a, and their discharge port sides are connected to the slack pipes, but in this embodiment, they are first connected to the reservoir 18a. This is constructed in a known manner, and a piston 19 in which a seal ring 20 is mounted inside a main body 22 is urged upward by a spring 21 and slidably fitted therein. An air chamber containing the above-mentioned spring 21 and a reservoir chamber for storing the working fluid are defined on both sides of the piston 19 and are provided on the suction side of the pump portion Pa of the hydraulic pump P according to the present invention. It is connected.

Next, details of the hydraulic pump P according to the present invention will be described with reference to FIG.

The hydraulic pump P according to the present invention comprises hydraulic pump parts Pa and Pb for both systems, and since they have the same configuration, only one pump part Pa will be explained, but For the part corresponding to, the suffix a is attached to one system, and the suffix b is attached to the other system.

A piston 6a having a seal ring g mounted on the outer periphery is slidably fitted to a cylinder body 24a having one end closed and the other end open, and the closed end of the cylinder body 24a and the piston 6a. A compression spring 8a is stretched between it and 6a. Further, the cylinder body 24a, and communicates with the liquid chamber H a with a built-in spring 8a, through holes 24aa, and forms a 24ab, forward directions to the master serial Sunda side respectively These from the wheel cylinder side Check valves 26a and 25a are connected.

The hydraulic pump portion Pb of the other system is similarly configured, but a cam plate A (also referred to as a cam ring) having a substantially rice ball shape is formed between the pistons 6a and 6b. The central axis C is concentrically connected to the rotating shaft of the electric motor M. This is a protrusion P having the same shape at the maximum distances equal to each other at intervals of 120 degrees from the axis of the central axis C. ₁ , P₂ , P₃ Is formed. Each protrusion P₁ , P₂ While P₂ , P₃ , And P₃ , P₁ The areas have curves of the same shape. And the liquid chamber in the cylinder body 24a, 24bHa,as well asHbThe spring force of the springs 8a and 8b stretched inside is sufficiently strong, and the portions of the pistons 6a and 6b protruding from the open ends of the cylinder bodies 24a and 24b are brought into contact with the outer peripheral portion of the cam ring A. There is.

The anti-skid brake device using the hydraulic pump according to the embodiment of the present invention is constructed as described above. Next, its operation will be described.

When the driver depresses the brake pedal 2, a large hydraulic pressure is generated in the cylinder body 4 due to the pedaling force assisting action of the booster unit 3, which is supplied via the pipe lines 7a and 7b to the supply valve 11a. , 12a and 11b, 12b to the wheel cylinders of the wheels 15a, 16a and 15b, 16b for braking.

Wheels 15a, 16a and 15b, 16b are each provided with a wheel speed sensor (not shown) in the vicinity thereof, and a computer (not shown) also applies a brake too much in response to a wheel speed signal from this wheel. If it is determined that the discharge valve 13a, 14a, 13b, 14b is energized, the supply valves 11a, 12a and 11b, 12b are also energized. As a result, the discharge valves 13a, 14a, 13b, 14b are in the communicating position, and the supply valves 11a to 12b are in the blocking position. As a result, the pressure liquid is discharged from the wheel cylinder side of the wheels 15a to 16b into the reservoirs 18a and 18b.

On the other hand, the anti-skid control is started and the driving of the hydraulic pump P is started. That is, the electric motor M starts driving. This rotating shaft rotates clockwise as shown in FIG. Therefore, the cam ring A, which is coaxial with this, also rotates clockwise. Therefore, the pistons 6a and 6b, which are constantly in pressure contact with this, reciprocate in the direction indicated by the arrow, but as shown in FIG. 3, the pistons 6a and 6b are moved once every 120 degrees while the cam ring A makes one rotation. Reciprocate. That P _1, P ₂ and P ₃ projecting portion P ₁ of the cam ring A, respectively, P ₂ in FIG. 3, and are shown to correspond to P _3, at this point, such as a piston 6a in FIG. 2, It takes a position most biased to the liquid chamber H a side, and then it is a reciprocating motion up to the first 60 degrees up to the protruding portion of P ₂ , and at the next 60 degrees (at this first position, The piston 6a is at the leftmost position in the figure.) The piston 6a moves to the right with the rotation of the cam ring A, and when the next protrusion P ₂ comes into contact with the piston 6a, the piston 6a is moved most forward. Move to moving position. In this way, when the cam ring A is rotated 360 degrees, that is, once, the piston 6a is reciprocated 3 times by the protrusions P ₁ , P ₂ and P ₃ . That is, the check valves 26a and 26b are opened from the reservoir chambers of the reservoirs 18a and 18b by the reciprocating movement of three times the rotational speed of the electric motor M to suck the brake fluid into the fluid chambers Ha and Hb , and When 6a and 6b move in opposite directions, that is, when going forward, the check valves 25a and 25b are opened through the through holes 24aa, 24ab and 24ba, 24bb, and the pressure liquid supply pipeline 7a, Supply pressure liquid to 7b side.

Since the embodiment of the present invention is constructed and operates as described above, the noise caused by the hydraulic pump is reduced, and only by forming the cam plate A, the motor can be used. Since it suffices to simply align and couple with the rotation axis of M, the cost of the entire anti-skid brake device can be reduced.

Although the embodiment of the present invention has been described above, the present invention is not limited to this, and various modifications can be made based on the technical idea of the present invention.

For example, in the above embodiment, the cam ring A has three protrusions P ₁ , P ₂ and P ₃ that are equidistant from the center of the central axis C. For example, six protrusions may be formed at intervals of 60 degrees, or, as shown in FIG. 4, a cam plate B having a substantially elliptical shape may be aligned and fixed to the rotation shaft of the electric motor M with its central axis C ′. You may ask. In this case the central axis C 'butt out section Q ₁ axis is truly a maximum distance is in the equidistant, Q ₂ by the piston 6a respectively, in FIG 2, 6b moves rightmost, or to the left, the motor M Since the pistons 6a and 6b can be reciprocated twice by one rotation of the rotary shaft, the effect of the present invention can be obtained.

Further, in the above embodiment, the invention is applied to the anti-skid brake device, and the pump sections Pa and Pb are provided in the two systems respectively, but it is also applicable to the one-system brake device. In this case, of course, only one of Pa and Pb is required.

Further, in the above embodiment, two through holes 24aa, 24ab are formed in the cylinder bodies 24a, 24b of the respective hydraulic pump parts Pa, Pb so as to communicate with the liquid chambers Ha , Hb . However, one of these may be omitted. For example, only 24aa and 24ba are connected, and for example, a Y-shaped pipe is connected to this, a check valve whose forward direction is toward the master cylinder side is connected to one branch portion of this, and the pressure liquid supply line is connected. Connect the reservoir chamber of the reservoir to the other branch part, and connect the common part of the Y-shaped conduit, that is, the check valve whose forward direction is the direction toward the through holes 24aa, 24ba. You may

Further, although the above embodiment is applied to the anti-skid brake device, the present invention is of course applicable to general hydraulic equipment.

Further, by changing the shape of the cam, it is possible to change the suction and discharge times to make the movement of the brake fluid more efficient.

In the above embodiment, the strokes of the pistons 6a and 6b are assumed to change in a substantially sinusoidal manner as shown in FIG. It may be designed using. In this case, a constant velocity cam, a constant acceleration cam, and the like are conceivable, but they may be formed based on the respective diagrams.

[0027]

[Effect of device]

 As described above, according to the hydraulic pump of the present invention, it is possible to reduce the generation of noise and reduce the manufacturing cost.

[Brief description of drawings]

FIG. 1 is a piping system diagram of an anti-skid brake device using a hydraulic pump according to an embodiment of the present invention.

FIG. 2 is a sectional view showing details of the hydraulic pump in FIG.

FIG. 3 is a time chart showing the operation of the hydraulic pump.

FIG. 4 is a front view showing a modified example of the cam ring.

[Explanation of symbols]

 6a piston 6b piston 8a spring 8b spring 24a cylinder body 24b cylinder body 24aa through hole 24ab through hole 24ba through hole 24bb through hole 25a check valve 25b check valve 26a check valve 26b check valve A cam ring C central shaft M machine Hydraulic pump

Claims (1)

[Scope of utility model registration request] 1. A cylinder body whose one end is closed, a piston which is slidable by mounting a seal ring in the cylinder body, and which is stretched between the piston and the closed end side of the cylinder. A spring for urging the piston toward the opening end side of the cylinder body, an end portion of the piston on the opening end side of the cylinder body, a cam ring that constantly abuts at its outer peripheral portion by the spring force of the spring, and the center of the cam ring. An electric motor that rotationally drives the cam ring around an axis of a shaft, a liquid chamber defined between the piston and a closed end of the cylinder body, and a liquid chamber that communicates with the liquid chamber and is connected to the cylinder body. The cam ring has at least one through hole formed therein, and the cam ring has, on the outer peripheral portion thereof, two or more protruding portions formed at equal maximum distances from the axial center of the central axis at equal angular intervals. Tosu Hydraulic pump.