JP2544571Y2 - Hydraulic pump device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to a plunger-type hydraulic pump device used for, for example, a vehicle brake system, and is particularly effective in reducing noise due to impact caused by pump operation. Technology.

2. Description of the Related Art A plunger-type hydraulic pump device is known as a high-pressure pump, and generally includes a main body having a cylinder hole with one end closed, and a plunger that movably fits into the cylinder hole of the main body to partition a pressure chamber. And a drive mechanism for moving the plunger from the inoperative position toward the pressure chamber.

The pressure chamber in the cylinder hole has an inlet side communicating with the hydraulic fluid reservoir through an inlet valve and an inlet passage, and an outlet side communicating with a consumption circuit such as a brake circuit through an outlet valve and an outlet passage.

Although the inlet valve and the outlet valve are generally constituted by a check valve, a technique is known in which the inlet valve is formed into a spool valve by using the movement of a plunger. With that technology,
A groove is formed on the inner periphery of the cylinder hole through a step, while a recess is formed on the outer periphery of the plunger, and the recess and the groove intersect with the movement of the plunger, thereby forming an inlet passage. Communicate with or shut off the pressure chamber. For the above, see, for example, JP-A-59-138786.

Such a hydraulic pump device can be classified into two types from the viewpoint of the arrangement of the liquid passages. The first type has a liquid passage arranged only outside the reciprocating plunger, and the second type has a liquid passage arranged inside the plunger (internal space). The pump technology disclosed in the above-cited Japanese Patent Application Laid-Open No. 59-138786 is one of examples belonging to the first type.

By the way, unlike the first type, in the second type, as shown in the official gazette of Japanese Utility Model Application Laid-Open No. 2-67083, for example, the plunger normally runs in the radial direction to communicate with the inside and outside of the plunger. A plurality of through holes are provided. In order to secure a sufficient flow passage area, these through holes must have a considerably large diameter.

Therefore, in the case of the second pump, since the through hole itself is large, the actual amount of movement (stroke) of the plunger in the axial direction for performing the pumping operation is relatively large.

(Problem to be Solved by the Invention) As a countermeasure in the second type, a technique has been developed in which a shallow recess is provided over the entire circumference of the plunger itself, and the plurality of through holes are formed in the recess. .

The inventor considered such a second type of developed technology, and further noticed abnormal noise generated by the pumping action. That is, when the recess on the plunger side crosses the step of the groove on the cylinder hole side, the hydraulic fluid tends to enter the slight gap between the plunger and the cylinder hole from the recess side and return. The impact of the returned liquid was severe, which seemed to be producing unusual noise.

In this regard, in the development technology described above, the shallow recess on the plunger side is provided exclusively around the entire circumference of the plunger, but if the recess is divided in the circumferential direction, the abnormal noise may be effectively reduced. Do you get it.

The present invention has been made based on the results of such studies, and has as its object to provide a technology capable of effectively solving the problem of noise in a hydraulic pump device having a spool valve-like inlet valve.

(Summary of Invention) In this invention, as shown with reference to the drawings corresponding to the embodiments, the recess 70 is divided into a plurality in the circumferential direction of the plunger 40, and furthermore, in each of the divided recesses, A lateral hole 40b for communicating with a communication hole 40a inside the plunger 40 is formed.
For example, the recess can be divided into two parts by forming the plunger with a two-sided width.

Thus, the plunger can be smoothly guided, and the noise can be effectively reduced without lowering the discharge efficiency of the pump.

Preferably, steps 70 before and after the plurality of divided recesses
a, 70b is cut out at step 70a on the side away from pressure chamber 42
75 should be provided. Thereby, noise can be more effectively prevented.

(Embodiment) FIG. 1 is a sectional view showing a main part of a hydraulic pump device to which the present invention is applied.

The body 11 of the hydraulic pump device has a stepped cylinder hole 12
There is. The inside of the cylinder hole 12 is a chamber for accommodating the drive mechanism, and the opening is liquid-tightly closed by a plug 14 holding a seal ring 13. The inside of the plug 14 is hollow, and each component is contained in the cylinder hole 12 including the hollow space 14a.

First, there is a sleeve member 20 along the axis of the cylinder hole 12. The sleeve member 20 has a two-part structure of a first sleeve 21 and a second sleeve 22, which are connected in the axial direction. A gasket 23 sandwiched between the ends of the sleeves 21 and 22 makes the joint liquid-tight. The sleeve member 20 is
As the plug 14 is screwed to the main body 11, the flange 21a in the middle of the first sleeve 21 hits the step 11a of the main body 11,
The end of the second sleeve 22 contacts the bottom of the plug 14, so that the first and second sleeves 21, 22 are fixed in the cylinder hole 12 in an integrated form. First
And, the second sleeves 21 and 22 have through holes 31 and 32 penetrating from end to end, respectively.

The diameter of the through hole 31 of the first sleeve 21 is uniform. A plunger 40 is movably fitted into the through hole 31 from one end side to define a pressure chamber 42 inside the sleeve member 20. The plunger 40 reciprocates in the through hole 31 by a driving mechanism including the cam 43 while being guided by the first sleeve 21. Since the cam 43 having a circular cross section is connected to the rotating shaft of a motor (not shown), and both shafts are eccentric by a predetermined size δ, the stroke of the plunger 40 is 2δ.
It is. That is, the plunger 40 is movable within a range of 2δ from the inoperative position shown in the figure (the position where the plunger 40 is farthest from the plug 14 side) toward the pressure chamber 42 side. The return spring 45 applies a force to bring the outer end of the plunger 40 into contact with the peripheral side surface of the cam 43.

A communication hole with a part of the plunger 40 located in the through hole 31
There is 40a. On the other hand, this communication hole 40a communicates with the pressure chamber 42,
On the other hand, the plunger 4 passes through the two lateral holes 40b and the recess 70.
0 side outside contact. The recess 70 is located halfway in the axial direction of the plunger 40. Therefore, the plunger
The recess 40 is guided by the two portions 401 and 402 before and after the recess 70 despite the presence of the recess 70 whose thickness is reduced, so that the recess 40 smoothly reciprocates in the through hole 31. Portion 40 close to pressure chamber 42
2 have two V-shaped grooves 403 on the outer circumference.
403 serves as a sump for lubrication.

Here, note the recess 70 in the middle of the plunger 40. These recesses have heretofore been annular over the entire circumference, but here there are two recesses 70 at 180 ° apart from each other on the outer circumference of the plunger 40. The two recesses 70 are separated by a connection 404 connecting the two plunger portions 401, 402, as FIGS. 2 and 3 make clear. Each recess 70 is wider than the opening area of the lateral hole 40b,
It has steps 70a and 70b at the front and back. In this example, a triangular cutout 75 is provided at the center of the step 70a on the side remote from the pressure chamber 42.

In relation to the recess 70 on the plunger 40 side, the first sleeve 21 side also has a lateral hole 21b communicating between the inside and the outside, and a groove 80 extending all around. The grooves 80 and the recesses 70 communicate with each other when the plunger 40 is in the non-operation position, whereas the groove 80 and the recess 70 close each other when the plunger 40 moves by a predetermined amount from the non-operation position to the pressure chamber 42 side. In a relationship. Thereby, the groove 80 and the recess 70 constitute the inlet valve 47. The inlet valve 47 opens or closes when the end of the step 70a of the recess 70 on the plunger 40 side contacts the end of the step 80b of the groove 80 on the first sleeve 21 side. Therefore, the notch 75 at the center of the step portion 70a is
It acts to buffer the closing action of 7. Inlet valve 47
The communication between the pressure chamber 42 and the inlet passage communicating with the hydraulic fluid reservoir (not shown) is, of course, interrupted.

On the other hand, the through hole 32 of the second sleeve 22 is stepped,
From the side closer to the gasket 23, there are three stages of a small diameter portion 32a, a medium diameter portion 32b, and a large diameter portion 32c. The small diameter portion 32a is continuous with the middle diameter portion 32b through the step portion 22a orthogonal to the axis, and the middle diameter portion 32b is continuous with the large diameter portion 32c through the loosely tapered step portion 22b.

The small diameter portion 32a faces the through hole 31 on the first sleeve 21 side,
This is a section that partitions the pressure chamber 42 together with the plunger 40.
Further, the middle diameter portion 32b and the large diameter portion 32c are connected to the check valve 50 on the outlet side.
This is the part for housing the casing 60 that accommodates The casing 60 includes a seat member 61 provided with a valve seat 61a at one end, and a shuttle-type valve body 62. The seat member 61 and the valve body 62 are integrally fixed by caulking. The check valve 50 in the casing 60 includes a ball 51 that can be seated on the valve seat 61a, and a valve spring 52 that biases the ball 51 toward the valve seat 61a. The valve opening pressure of the check valve 50 is, for example, about 20 kg / cm ² .

Now, at the time of operation of the pump, every time the inlet valve 47 closes,
The liquid pressure in the pressure chamber 42 rises sharply. Also, the casing 60
Has a seal ring 63 on its outer periphery, so that it receives the hydraulic pressure when the pump operates. Therefore, in order to make the casing 60 function as a damper piston, an elastic member 65, for example, a ring-shaped rubber spring is interposed in a portion of the casing 60 on the plug 14 side. Elastic member 65
When the fluid pressure rises steeply, the casing itself is deformed by the force from the casing 60, and the casing 60 is allowed to move to the bottom side of the plug 14. Then, since the impact force when the inlet valve 47 closes is reduced, the cam is passed through the plunger 40.
43, the reaction force transmitted to the drive mechanism such as the motor is also reduced,
Vibration and noise due to the reaction force are also reduced.

The pressure fluid discharged through the check valve 50 is supplied to the valve body 62.
And the respective holes 62a and 22c of the second sleeve 22 and the main body 1
It is supplied to a consumption circuit such as a brake circuit through an exit passage including one exit hole 11c.

Further, in the embodiment shown in the drawings, the recess 70 on the side of the plunger 40 is divided into two in the circumferential direction in order to facilitate processing, but it may be divided into three or four.

Furthermore, in the embodiment shown in the figure, the casing 60 of the check valve 50 functions as a damper piston, and the notch 75 is provided on one side of the recess 70.
It is possible to suppress a steep rise in hydraulic pressure immediately after the 47 is closed, and it is possible to further reduce noise and vibration. However, noise can be significantly reduced only by dividing the gap at the inlet valve 47.

(Effects of the Invention) According to the invention, the pump device having the liquid passage inside the plunger 40 is improved, and the passage formed by the gap of the portion constituting the inlet valve 47 is divided in the circumferential direction, so that the passage is formed through the passage. The impact of the liquid to be returned can be reduced, and the noise can be effectively reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a main part of one embodiment of the present invention, FIG. 2 is a partial view of a plunger viewed from a direction F in FIG. 1, and FIG. It is a figure showing the outline of the plunger of a part. 11 ... body, 12 ... cylinder bore, 40 ... plunger, 40
a ... Internal communication hole, 40b ... Horizontal hole, 42 ... Pressure chamber, 43 ...
... cam, 47 ... inlet valve, 70 ... recess, 75 ... notch, 80
……groove.

Claims (2)

(57) [Scope of request for utility model registration] 1. A main body having a cylinder hole closed at one end, a plunger movably fitted into the cylinder hole of the main body to define a pressure chamber, and the plunger being moved from a non-operation position toward the pressure chamber. A driving mechanism for moving;
An outlet passage connecting the pressure chamber to a consumption circuit, a groove formed on the inner periphery opposite to the closed end side of the cylinder hole through a step, and an inlet connecting the groove to a hydraulic fluid reservoir A passage, a recess formed by reducing the outer circumference of the plunger so as to communicate with the inlet passage through the groove when the plunger is in the inoperative position, and connecting the recess to the pressure chamber. And a communication hole provided inside the plunger, wherein the effective pressure is applied when the recess exceeds the step according to the movement of the plunger toward the pressure chamber. A hydraulic pump device in which the recess is divided into a plurality in the circumferential direction of the plunger, and a lateral hole for communicating with a communication hole in the plunger is formed in each of the divided recesses. 2. The method according to claim 1, wherein the plurality of recesses have step portions before and after along the axial direction of the plunger.
2. The hydraulic pump device according to claim 1, wherein there is a notch extending in the axial direction.