JPH0825466B2 - Structure of valve shaft in control valve - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to the structure of a valve shaft in a control valve used in, for example, power steering, and in particular, the strength of the valve shaft is improved by setting the shape of the groove of the valve shaft. Excellent and simplifies work.

[Conventional technology]

Conventional valve shafts of this type include, for example, Japanese Patent Application No.
There is one as shown in FIG. 5 described in 61-228456. In the structure of the valve shaft S shown in FIG. 5, a drain hole 5 through which a torsion bar (not shown) penetrates is formed at the center, and four types of grooves are formed on the outer peripheral surface along the axial direction. Has been formed. Reference numeral 1 is a first groove, which is a groove that receives the supply hydraulic pressure from the power steering pump and sends it out toward the power cylinder, and 2 is a second groove, which is used when steering to the left or right. A groove for receiving the return liquid from the power cylinder and returning it to the drain hole 5, 3 is a third groove, which receives the return liquid from the power cylinder when the steering wheel is turned to the other of the left and right sides and drains. The drain hole 5 receives the return liquid from the controller that adjusts the hydraulic pressure supplied to the power cylinder according to the vehicle speed, and the drain hole 5 is a groove for returning to the hole 5.
It is a groove to return to. Reference numeral 6 is a communication hole that connects the groove 4 and the drain hole 5. In FIG. 5, the first to fourth grooves and the communication hole 6 are shown.
3 groups are formed.

Each of the grooves 1 to 4 is formed by cutting using three types of cutters shown in the drawing or by changing the angle with two types of cutters. That is, the grooves 1 and 4 are cutters A whose tip cutting blades have a rectangular cross section, and the grooves 2 are cutters B whose cross section is trapezoidal in which the tip cutting blade is inclined on one side, and grooves 3
Is a cutter C having a trapezoidal cross section in which the tip of the tip is slanted on the other side, and these cutters are relatively moved in the axial direction of the valve shaft S for cutting, or the grooves 2 and 3 are the tip of the tip. Is once similarly cut with a cutter having a quadrangular cross section, and then similarly cut so as to form an inclined side wall by changing the angle of the cutter.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional valve shaft S, three types of cutters A, B, C for cutting the grooves 1 to 4 are used.
Not only is it necessary to cut each groove 1 to 4 toward the center of the ball shaft S having a circular cross section, but in order to cut each groove at 12 places, the cutting direction of the cutter is 12 in total in the centripetal direction.
Must be set times. Even if two kinds of cutters are used for cutting, 6 grooves out of 12 must be cut twice, which means 18 cutting steps in total. Therefore, there is a problem in that the manufacturing cost of the conventional valve shaft is high in terms of equipment cost and man-hours.

Further, since each of the grooves 1 to 4 is cut in the centripetal direction as described above, the sectional convex portion 7 between the groove 1 and the groove 2 and the sectional convex portion 8 between the groove 1 and the groove 3 are The width at the groove bottom is smaller than the width at the outer peripheral surface of the valve shaft S. Therefore, it is necessary to maintain the overall size of the valve shaft S at a predetermined size in order to make the cross-sectional convex portions 7 and 8 sufficiently strong, and it is difficult to make the valve shaft S sufficiently small. There were also problems.

Therefore, in order to solve these problems, the inventors invented a valve shaft S shown in FIGS. 3 and 4 and used a cutter D having three blades and a cutter E having two blades. It was devised to cut each groove 1 to 4 so that a plurality of grooves could be cut at one time. However, in the case of FIG. 3, each of the grooves 1 to 4 needs to be cut twice, and in the case of FIG. 4, the two grooves 2 and 3 need to be cut twice. Also in this case, the cutters D and E become large in size, and there is a problem that equipment cost and man-hours end up increasing.
I couldn't adopt the plan of 4 figures.

Thus, in the above-mentioned conventional technique, it is an unsolved subject to reduce the equipment cost and man-hours in manufacturing the valve shaft and to downsize the valve shaft.

[Means for solving the problem]

In the valve shaft of the present invention, the first groove on the outer periphery is formed in a substantially quadrangular cross section by the side walls facing each other and parallel to each other, and the bottom forming a surface perpendicular to the side walls. A second groove and a third groove, which are adjacent to both sides of the first groove and are parallel to the first groove, respectively, and one side wall parallel to the side wall of the first groove and the first groove. The side wall and the other side wall that are parallel to each other form a substantially triangular cross section.

[Action]

Since the surfaces forming the second and third grooves are parallel to the surface forming the first groove, the first to third grooves are formed by the same cutter and the cutting directions of the cutters are made the same. It can be cut as it is. Therefore, the number of cutters and the number of times the cutting direction is set can be reduced.

In addition, the first to third while keeping the cutting direction of the cutter the same.
Since the groove can be cut, the width of the convex portion formed between the grooves is the same at both the outer peripheral portion of the valve shaft and the bottom portion of the groove, so that the strength of the convex portion is increased.

〔Example〕

FIG. 1 is a diagram showing a first embodiment of the present invention. The valve shaft S includes a first groove 1, a second groove 2 and a third groove 3.
This is the same as the prior art shown in FIG. 5 in that it has three sets of grooves consisting of the groove 3 and the fourth groove 4, and further has a drain hole 5 and a communication hole 6.

In this embodiment, the grooves 1 to 3 are further configured as follows. That is, the first groove 1 is formed with both side walls 1a and 1b facing each other and parallel to each other, and a bottom 1 forming a surface perpendicular to these side walls.
With c, the cross section is formed into a substantially quadrangular shape. The reason why the shape is a substantially quadrangle is that the side walls 1a, 1b and the bottom 1c appear as straight lines in a cross section, but the other one side is not exactly a quadrangle because the arc of the outer circumference of the valve shaft S appears. Is. In the groove 1, the center line CL in the width direction coincides with the radial direction of the valve shaft S, and thus the surface of the bottom 1c is orthogonal to the center line CL.

The grooves 2 and 3 are parallel to the side walls 1a and 1b of the groove 1 and one side wall 2
The a and 3a and the other side walls 2b and 3b that are parallel to the bottom 1c of the groove 1 are formed into a substantially triangular cross section. The substantially triangular shape means that the side walls 2a, 2b, 3a, 3b appear as straight lines in the transverse cross section as in the case of the groove 1, but the other side has an accurate circular arc because the arc of the outer circumference of the valve shaft S appears. Because it will not be.

The groove 4 has the same cross-sectional shape as the groove 1, and the center line CL in the width direction thereof, like the groove 1, also coincides with the radial direction of the valve shaft S.

The valve shaft S is formed with three sets of the above-mentioned grooves 1 to 4 as shown in the figures X, Y and Z, which are fitted in the valve body to control the hydraulic fluid of the power steering as in the prior art. To do.

Next, the cutting direction of the grooves 1 to 4 will be described. When cutting the grooves 1 to 4 forming the group of X, the grooves 1 to 3 are sequentially cut by the single cutter F. The order of cutting in the grooves 1 to 3 may be any, but here, it is assumed that cutting is performed from the groove 1. The following operations are relative operations of the cutters F and G and the valve shaft S. Therefore, in the following description, the cutter is moved with respect to the valve shaft S, but the valve shaft S may be moved with respect to the cutter, as a matter of course.

First, the groove F is cut by sequentially advancing the cutter F in the same direction with the center line of the cutter F facing the center of the valve shaft S (that is, aligned with the center line CL of the groove 1 to be cut). By using a cutter F whose tip has a right angle on the left and right, the groove 1 having the above-mentioned shape can be cut to form the side walls 1a, 1b and the bottom 1c thereof.

When the cutting of the groove 1 is completed, the cutter F is retracted while keeping the posture (that is, the direction with respect to the center of the valve shaft S), and the posture is kept as it is to move only the position to the planned cutting position of the groove 2. The cutter F is moved forward in parallel with the case where the groove 1 is cut by. This results in groove 2
Is cut. At this time, since the center line of the cutter F does not pass through the center of the valve shaft S, the groove 2 is not symmetrical in the width direction, and is a right-angled V-shaped groove as shown in the drawing.

Further, the cutter F is moved to the planned cutting position of the groove 3 while keeping the posture, and the groove 3 is similarly cut. Since the grooves 2 and 3 have the same distance with respect to the groove 1, they are formed symmetrically with respect to the groove 1.

The groove 4 is cut by the cutter G in the same manner as the groove 1, but if the shape of the groove 4 is the same as the groove 1, the groove G may be cut by the cutter F without using the cutter G. The cutting of the groove 4 is performed by advancing the center line of the cutter G toward the center of the valve shaft S as in the case of the groove 1.
Either the grooves 1 to 3 or the groove 4 may be cut first.

Thus, the grooves 1 to 4 in the set X are cut, but the groove 1
It is also possible to cut any one of 3 to 3 and the groove 4 first in each set X, Y, Z and cut the other later. For example,
The grooves 1 to 3 of each set may be cut first, and the remaining three grooves 4 may be cut thereafter.

Thus, when the grooves 1 to 4 are cut, the protrusion formed between the adjacent grooves has the same width at the tip end and the base end or the width at the base end is wide. Is sufficiently secured, and only one or two cutters are required for cutting.

Further, the setting of the angle of the cutter for cutting the grooves 1 to 4 with respect to the valve shaft S is as follows. That is, the groove 1
When cutting 4 with one cutter F, it is set 6 times at a pitch of 60 degrees, and when cutting grooves 1 to 3 with cutter F and cutting groove 4 with cutter G, the cutter is F
Is set 3 times at 120 degree pitch, and cutter G is also 3 times at 120 pitch
Will be set once. In this way, when cutting with only one cutter F, and also when cutting with both cutters F and G, it is sufficient to set the angle of the cutter 6 times.

FIG. 2 is a cross-sectional view of the valve body fitted onto the valve shaft S of FIG. Three sets of grooves 11, 12, 13, and 14 are formed on the inner peripheral surface of the valve body to control the flow of liquid between the grooves 1 to 4 of the valve shaft S as is well known. To do. Further, these grooves 11 to 14 and the inner peripheral surface of the valve body in which the grooves are not formed are connected to each external hydraulic device via radial through holes which are not labeled.

In the illustrated example, the grooves 12 and 14 of the grooves 11 to 14 have a wide width and the same width, and the grooves 11 and 13 have a narrow width and the same width. Located symmetrically with respect to the center of the valve body. Therefore, in order to cut these twelve grooves, the cutter H having a wide width and the cutter I having a narrow width are attached to a tool (not shown) in a state of being set in the direction of 180 degrees, and cutting is performed. With this, two grooves can be cut at the same time by one processing,
It is possible to cut 12 grooves each by machining 6 times.

The valve body shown in FIG. 2 is an example of a valve body that is combined with the valve shaft S shown in FIG. 1. Therefore, another valve body may be fitted onto the valve shaft S shown in FIG. Of course, it is also good.

〔The invention's effect〕

As described above, according to the present invention, since the surfaces forming the second and third grooves are both parallel to the surface forming the first groove, the first to third grooves are It is possible to cut with the same cutter and with the same cutting direction of the cutter. For this reason, the number of cutters and the number of times the cutting direction is set can be reduced, which has the effect of reducing the equipment cost and man-hours for manufacturing the valve shaft.

In addition, the first to third while keeping the cutting direction of the cutter the same.
Since the groove can be cut, the width of the convex portion formed between these grooves is the same both in the outer peripheral portion of the valve shaft and the bottom portion of the groove. Also, the second and third grooves are
Since one side wall that is parallel to the first groove and the side wall and the other side wall that is parallel to the bottom of the first groove are formed to have a substantially triangular cross section, a set of first to third grooves is formed. When a plurality of grooves are formed on the outer circumference of the valve shaft, the width of the convex portion formed between the adjacent grooves of each set is larger at the bottom of the groove than at the outer circumference of the valve shaft. Further, even when the fourth groove is formed adjacent to the first to third groove sets, the same applies to the convex portion between the first to third groove sets and the fourth groove. . Thus, the strength of the convex portion formed between the grooves is increased, so that the valve shaft has sufficient strength even if the valve shaft is downsized, and the valve shaft as well as the entire control valve can be downsized. There is also the effect that it will be possible.

[Brief description of drawings]

1 is a cross-sectional view showing an embodiment of the present invention, FIG. 2 is a cross-sectional view showing an example of a valve body externally fitted to the valve shaft of FIG. 1, and FIG. 3 is a process of creating the present invention. Fig. 4 is a cross-sectional view of the first valve shaft devised, Fig. 4 is a cross-sectional view of the second valve shaft devised in the process of creating the present invention, and Fig. 5 is a cross-sectional view showing the prior art of the valve shaft. It is a figure. AI: Cutter, S ... Valve shaft, X, Y, Z ...
Groove set, 1 ... first groove, 1a, 1b ... side wall, 1c ... bottom,
2 ... second groove, 2a, 2b ... side wall, 3 ... third groove, 3a,
3b ... Side wall, 4 ... Fourth groove, 5 ... Drain hole, 6 ...
Communication hole.

Claims (1)

[Claims] 1. A valve body having a cylindrical shape, and a valve shaft rotatably fitted in the valve body, wherein a plurality of grooves forming liquid passages are formed on an inner peripheral surface of the valve body and an outer peripheral surface of the valve shaft. The groove formed in the valve body and the groove formed in the inner peripheral surface, and the shoulder formed in the corner formed between the groove forming the valve shaft and the outer peripheral surface. In the control valve that controls the hydraulic pressure supplied to the actuator by forming a throttle in the fluid path between the both sides of the first groove on the outer periphery of the valve shaft, facing both sides and parallel to each other. Second and third grooves, which are formed in a substantially rectangular cross section by the bottom forming a right angle surface, are adjacent to each other on both sides of the first groove and are parallel to the first groove, One parallel to the side wall of the first groove And a side wall parallel to the bottom of the first groove, each of which is formed in a substantially triangular cross section.