JPS637573Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power steering device, generally referred to as power steering, used to reduce the steering force of an automobile.

In this type of power steering device, the rack-and-pinion type has a problem in terms of installation space in the vehicle due to the location of the control valve that switches the hydraulic circuit to the power cylinder, which is the output part. There is. That is, conventionally in this type of device, a rotary type control valve is often used as the control valve, and the rotary valve is usually arranged in series on the input shaft between the handle and the pinion that meshes easily. Therefore, such a structure requires a valve housing that is long in the axial direction and has a large diameter for disposing the valve, and this valve housing becomes bulky in the direction of the input shaft. However, it is desirable for modern cars to have compact bodies and large interior spaces.
For this reason, the above-mentioned valve housing that rises toward the handle becomes an obstacle, and there is a particular demand for downsizing in the direction of the input shaft.

In addition, the above-mentioned rotary valve has a configuration in which valve switching is performed using a torsion bar, etc., which makes the structure of each part complicated, making manufacturing and assembly troublesome, and making it expensive.
Furthermore, there were other drawbacks such as the overall weight of the device being heavy.

In order to solve these problems, a structure was proposed in which a spool valve was used as the control valve, and the spool valve was placed at the bottom of the rack on the opposite side from the handle, for example, in Japanese Patent Application Laid-Open No. 53-51828. However, in this case, depending on the amount of protrusion of the valve housing, there are problems such as hitting the ground due to sudden vertical movement of the vehicle.
It is desired to further downsize the entire device.
In addition, in order to switch the spool valve mentioned above as the handle is operated, the tip of the input shaft is configured to be swingable, and the relative displacement that occurs between the rack and pinion is often used. Poor engagement between the pinion and the rack is likely to occur, resulting in poor handle operability and valve operation reliability, and it is desired to have a structure that can operate more reliably.

Furthermore, in order to switch and control the spool valve mentioned above, a gear provided on the input shaft on the handle side and a gear on the steering wheel side that easily mesh with each other are meshed with a gear on the output shaft side arranged parallel to the input shaft. An idle gear is provided so as to be pivotally supported by a frame portion of a movable member that is supported movably in a direction orthogonal to each of the input and output shafts and the rack, and the idle gear is provided so as to be supported in a frame portion of the movable member so as to be movable in a direction perpendicular to each of the input and output shafts. A device having a structure in which a spool valve is provided on the outer periphery of a valve rod and the spool valve is actuated by the movement of the spool valve has been proposed, for example, in Japanese Patent Publication No. 50-2141.

However, in such conventional devices, the valve rod portion of the movable member on which the spool valve is provided is
Since the input and output shafts are easily orthogonal to the body and extend in the direction of movement of the idle gear, it is inevitable that the overall size of the device will increase.
In addition, there are many components such as the output shaft, which is the transmission system from the input shaft to the easy side, and the structure is complex, requiring precision in each part, resulting in high costs. It was a big problem.

The present invention was developed in view of the above circumstances, and it is an idle gear that is interposed between the pinion and rack that constitute the steering gear and meshes with each other to transmit rotation, and is moved in the longitudinal direction of the rack. It is simple in that it is pivotally supported on the steering body in a free state, and its shaft extension end is engaged in a switchable and controllable state with a spool valve for switching the hydraulic circuit, which is arranged in the steering body in parallel with the rack. This structure allows spool valves etc. to be efficiently placed inside the body, making it possible to reduce the size and weight of the entire device including the direction of the input shaft. In addition, we provide a power steering device that is superior in terms of cost, can easily and reliably control the spool valve using the displacement of the idle gear, and has excellent steering operability. It is something to do.

Hereinafter, the present invention will be explained in detail using embodiments shown in the drawings.

Fig. 1 shows an embodiment of the rack-and-pinion type power steering device according to the present invention. A pinion 2 serving as a gear is formed. Reference numeral 3 denotes a rack having a rack gear 4 disposed perpendicularly to the input shaft 1 and receiving rotation transmission from the pinion 2 in the axial direction of the outer circumference. It forms part of a steering link mechanism that is extended and steers wheels arranged at both ends of the link mechanism.

The pinion 2 and rack 3 described above are disposed facing each other at a predetermined distance within a steering body 5 consisting of a pair of gear housings and valve housings 5a and 5b. In this case, a piston (not shown) for generating steering assist force is provided in a part of the longitudinal direction (axial direction) of the rack 3, and a piston (not shown) is provided in a part of the longitudinal direction (axial direction) of the rack 3. A cylinder is formed. In addition,
6 is a support member that supports the rack 3 from the opposite side of the pinion 2; 7 is a spring retainer having a spring 7a that biases it toward the pinion 2; and 8a, 8b.
9 are a pair of bearings that pivotally support the input shaft 1, and 9a, 9b, and 9c are sealing materials for sealing the interior space of the steering body 5.

Now, according to the present invention, an idle gear 10 is provided which is interposed between the pinion 2 and the rack 3 constituting the above-mentioned steering gear and meshes with each other to transmit rotation. A spool for switching hydraulic circuits, which is pivotally supported on the steering body 5 side so as to be movable in parallel with the longitudinal direction, and whose extended end of the pivot shaft 10a is disposed in the steering body 5 in parallel with the rack 3. It is configured to be engaged with the valve 11 in a switchable and controllable state. That is, the pivot shaft 10a of the idle gear 10 is connected to the housing 5.
It is fitted through a bearing 13 into an elongated hole 12 that is bored opposite to a and 5b. This long hole 12 is
As is clear from FIG. 2, the cross section is approximately elliptical, and as the pinion 2 rotates, the pivot shaft 10a of the idle gear 10 extends parallel to the input shaft 1 through the elongated hole 12.
Displace the inside to the left and right. The state in which it is displaced in the left and right directions is shown by the dashed dotted line in the figure. In this case, it goes without saying that the idle gear 10 meshes with the pinion 2 and the rack gear 4 on the rack 3 in any of the left, right, or neutral positions to transmit the rotation thereof.

As shown in FIG. 1, one end of the pivot shaft 10a of the idle gear 10 is extended toward the valve housing 5b, and the center of the spool 14 of the spool valve 11 is disposed in parallel with the rack 3 inside the valve housing 5b. It is fitted into a hole 14a bored in the hole 14a. Therefore, when the idle gear 10 is displaced to either the left or right direction in FIG. 2, the spool 14 slides in the axial direction, as shown in FIG. 3, and the flow path within the valve is switched.

To briefly explain this spool valve 11 using FIG. 3, an opening at one end of a valve hole 11a formed in a valve housing 5b is closed with a bolt 15, and the spool 14 is located in the center with a pair of centering rings. It is placed in a state where it is biased from both sides by springs 16a and 16b. There are two annular grooves 17a and 17b on the outer periphery of this spool 14.
Further, annular grooves 18a, 18b, and 18c are formed at three locations on the inner periphery of the valve hole 11a. Of the annular grooves on the side of the valve hole 11a, a return boat 19 that communicates with an oil tank (not shown) opens in the annular groove 18b in the center, and pressure from an oil pump (not shown) opens in the annular grooves 18a and 18c on the outside of the annular groove 18b. An entry port 20 for supplying oil is open. As mentioned above, 21 and 22 are output ports that lead pressure oil to the left and right liquid chambers of the power cylinder, which are provided in the extension of the rack 3.
The annular groove 17a, 1 at the center of the spool 14
It opens into the valve hole 11a so as to communicate with the valve hole 7b. In addition, in FIG. 1, only the return port 19 is shown among the above-mentioned ports. Moreover, 14b is a through hole that communicates both sides of the spool 14.

What should be noted in such a configuration is that the spool valve 11, which is operated by the idle gear 10 interposed between the pinion 2 and the rack 3, is arranged parallel to the rack 3 in the gear housing 5a as close as possible. The main advantage is that the entire device can be configured compactly. That is, the valve housing 5b provided with the spool valve 11
is located on the lower side of the vehicle body in the actual installation state,
It is necessary to minimize the amount of protrusion, and according to the present invention, this can be made possible due to its configuration. In addition, the above-mentioned component devices are those that use rotary valves as in the past, those that have a structure in which the input shaft is swingable to switch the spool valve, and those that have a structure in which the input shaft is swingable to switch the spool valve, and there are also those that use a spool valve and an idler that is interposed between the output shaft. Compared to a device in which the switching operation is performed by a valve rod extending from a movable member that pivotally supports a gear, the overall structure is extremely simple and has the advantage of being easy to manufacture and assemble.

Further, according to the above-described configuration, the idle gear 10 is displaced in a desired direction by the pinion 2 that rotates as the handle is operated, and thereby the spool valve 11 can be easily and reliably switched. The rotation of the pinion 2, that is, the steering force is also reliably transmitted to the rack 3 via the idle gear 10. At this time, the power cylinder is activated by switching the spool valve 11 described above, and a light and quick steering operation can be performed.

Note that the present invention is not limited to the structural device of the embodiment described above, and the structure, shape, etc. of each part can be changed as appropriate, and various modifications can be considered.

As explained above, according to the rack-and-pinion type power steering device according to the present invention, the idle gear is interposed between the pinion and the rack that constitute the steering gear and meshes with each other to transmit rotation. The rack is pivotally supported on the steering body so that it can move freely in the longitudinal direction of the rack, and the extended end of the shaft can be switched to a spool valve for switching hydraulic circuits arranged inside the body in parallel with the rack. Because they are engaged, the spool valve can be efficiently placed inside the body despite the simple configuration with a small number of components, making the entire device smaller, lighter, and more compact, including the direction of the input shaft. In addition, each part can be processed,
It simplifies assembly, reduces costs, allows valve switching to be done easily and reliably, and has excellent handle operability, and has various practical effects.

[Brief explanation of the drawing]

The figures show one embodiment of the power steering device according to the present invention, FIG. 1 is a longitudinal sectional view showing the relationship between the pinion and the rack, and FIG. 2 is an explanatory diagram showing the operating state of the idle gear, which is a feature of the device. , FIG. 3 is a side sectional view of the spool valve. 1...Input shaft, 2...Pinion, 3...
Rack, 10... Idle gear, 10a... Axis, 11... Spool valve, 12... Long hole, 1
3...Bearing, 14...Spool.

Claims (1)

[Scope of utility model registration request] An idle gear is provided between the pinion and the rack constituting the steering gear and meshes with each other to transmit rotation, and the idle gear is pivotally supported by the steering body so as to be movable in the longitudinal direction of the rack. A power steering device characterized in that the shaft extension end thereof is engaged in a switchable and controllable state with a spool valve for switching a hydraulic circuit disposed in a steering body in parallel with the rack. .