Kabushiki Kaisha Sg

Honda Motor Co., Ltd.

Bridgestone Corporation

Yuji Matsuki

Wataru Ichikawa

Seiji Hirohashi

Yoshiaki Hirata

Yoshifumi Umemura

Toshiharu Nakagima

Yasuyuki Mizutani

Mikiya Ito

Shigeo Tsuru

Yuji Taya

Takeo Maruyama

Masaru Ohara

Shingi Hoshino

A braking apparatus performs its braking action by pressing a brake bush radially inwardly against a rod. The brake bush is pressed via a plurality of coned disk springs, each of which has a plurality of outer and inner radial recesses extending from its outer and inner peripheral edges, respectively. The outer and inner recesses are arranged in an alternating fashion along the circumference of the spring. As a brake piston moves in the axial direction of the rod, the inner peripheral edge of each of the springs is compressed or deformed radially inwardly. The brake piston is moved by compressed air supplied from outside. By increasing the radial length of each of the inner radial recesses of the coned disk springs in such a manner that the radial outward end of the recess is located far beyond the radial inward end of each adjacent outer radial recess, it is permitted to provide at least three or more coned disk springs around the brake bush. Thus, abrasion of each coned disk spring can be minimized, and durability of the braking apparatus can be greatly enhanced. Further, by forming each of the coned disk springs so as to have a rectangular sectional shape, it is possible for the braking apparatus to perform a sufficient braking function even when the outer and inner peripheral edges of the coned disk springs have been abraded to a considerable degree.

Braking apparatus operated via resilient deformation of coned disk

A spot welding machine includes tip electrodes mounted on the tips of the first and second arms, respectively, a pressing actuator for moving at least one of the first and second arms to apply a pressing force to the tip electrodes, an interelectrode distance detector for detecting a distance between the tip electrodes, and a brake for braking the actuator. The distance between the tip electrodes, i.e., interelectrode distance can be set at any desired intermediate distance between the maximum and minimum distances, by braking the actuator when the arms are opened to a desired degree. In this manner, it is made possible to effectively reduce the required operation time, and by suitably performing such a brake control, it is also made possible to effectively lessen an impact caused when the tip electrodes come into contact with plates to be welded. A speed control device may be provided which variably controls the moving speed of the actuator in accordance with the interelectrode distance. In such a case, it is permitted to properly control the moving speed of the arms and hence of the tip electrodes in response to the current position of the arms, and therefore the contact impact can be effectively lessened.

Spot welding machine

The rodless cylinder includes at least a cylinder tube and a piston, but it has no piston rod that is indispensable in the conventional cylinders. The article carrier is connected via the piston yoke to the piston and movable with parts and jigs placed thereon as the piston moves along the cylinder. At least one rod is fixed relative to the cylinder tube to extend in parallel with the direction in which the piston and hence the carrier moves. The sensor is provided to be movable along the rod as the piston moves. The sensor has a moving member movable along the rod as the piston moves within the cylinder tube, for detecting a current position of the piston in accordance with relative positional relation between the moving member and the rod. With such arrangements, the rodless cylinder as a whole has a higher rigidity against heavy load, and also the piston can be accurately positioned to stop at a desired position in its stroke.

Rodless cylinder apparatus

A decrease amount in plate thickness at a spot weld is detected at a predetermined time period when application of pressure is still maintained after termination of power supply to electrodes for spot welding. The decrease amount is correlated with the magnitude of diameter of nugget formed by spot welding, e.g., a larger diameter of nugget signifies a stronger the joint, and therefore, the quality of joint at the spot weld can be examined on the basis of the detected decrease amount. Since a value obtained by integrating plate thickness detection data of the spot weld during the predetermined time period is correlated, as the decrease amount is, with the magnitude of the diameter of a nugget, the quality of the joint may also be examined on the basis of this integrated value. There is provided, in a spot welding machine, a detector for detecting a stroke position of a cylinder for pressing electrodes or a detector for detecting a position of displacement of a tip portion of an arm interlocked with the movement of the electrodes and the distance between the electrodes, i.e., plate thickness, can be indirectly detected by the detector without adversely affecting efficiency of the spot welding work.

Method for checking a spot welded portion and spot welding machine

A linear guide includes a linear guide member provided over a guide range, a movable member being displaceable along the linear guide member and a ball bearing assembly provided on the movable member in a portion which comes in sliding contact with the linear guide member. A position detection device for the linear guide comprises the ball bearing assembly and a coil assembly and the ball bearing assembly has a casing and a succession of plural metallic balls disposed within the casing to form an endless ball array with each adjacent one of the balls being in close contact with another whereby the balls are linearly displaceable in accordance with displacement of the movable member. The coil assembly is provided on a part of the casing and includes a coil member which is excited by an ac signal. A magnetic path is formed through the ball located at the part of the casing and a reluctance change is produced in the magnetic path in accordance with displacement of the balls. One cycle of the reluctance change is determined by displacement corresponding to the diameter of the balls. An output signal responsive to the reluctance change is produced from the coil assembly.

Position detection using reluctance changes induced by displacement of

A first pattern which repeats change in the longitudinal direction with a predetermined pitch and a second pattern which changes in the longitudinal direction with a pitch which is different at least from that of the first pattern, both formed of a predetermined material, are disposed on a surface of a rod section. A detection head section is provided in proximity to the rod section, responds individually to the first pattern and the second pattern, changes its relation of correspondence to the respective patterns in accordance with its linear position with respect to the rod section and produces output signals in accordance with the relation of correspondence to the respective patterns. In accordance with the output signals corresponding to the respective patterns, first and second absolute position data of different ranges whose one cycle is constituted of one pitch of the respective patterns can be obtained. By combining these absolute position data, linear position of the detection head section with respect to the rod section can be specified in an absolute value. By disposing the first and second patterns in a mixed state on a single rod section, the construction of the device can be simplified.

Absolute linear position detection device

A first pattern which repeats change in the longitudinal direction with a predetermined pitch and a second pattern which changes in the longitudinal direction with a pitch which is different at least from that of the first pattern; both formed of a predetermined material, are disposed on a surface of a rod section. A detection head section is provided in proximity to the rod section, responds individually to the first pattern and the second pattern, changes its relation of correspondence to the respective patterns in accordance with it linear position with respect to the rod section and produces output signals in accordance with the relation of correspondence to the respective patterns. In accordance with the output signals corresponding to the respective patterns, first and secondd absolute position data of different ranges whose one cycle is constituted of one pitch of the respective patterns can be obtained. By combining these absolute position data, linear position of the detection head section with respect to the rod section can be specified in an absolute value. By disposing the first and second patterns in a mixed state on a single rod section, the construction of the device can be simplified.

On a circumferential side surface of a single cylindrical member constituting a main body of a rotor section are disposed, in parallel, a first pattern which repeats change in the circumferential direction with a predetermined pitch and a second pattern which has a change of one cycle with respect to one circumference. A detection head section which is provided in proximity to the rotor section changes its relation of correspondence to the respective patterns in accordance with rotational position of the rotor section and produces output signals corresponding to the relation of correspondence. A relatively rough absolute value of a rotational position within one rotation is established by an output signal produced in response to the second pattern and its accuracy is established with a high resolution by an output signal produced in response to the first pattern. By disposing the first and second patterns in parallel on the single cylindrical member of the rotor section, the construction of the device can be simplified.

Absolute rotational position detection device

This rotational position detection device comprises a stator section including primary and secondary windings and a rotor section disposed in such a manner that it is capable of performing relative rotational displacement with respect to the stator section. A conductive substance portion is provided in the form of a predetermined pattern. The amount of flux passing through the conductive substance portion of the rotor section changes in accordance with a relative rotational position of the rotor section with respect to the stator section and therefore an eddy current flows through the conductive substance portion. Reluctance is caused to change by a loss due to this eddy current and a secondary output signal corresponding to the rotational position is produced in the windings of the stator section. The pattern of the conductive substance portion can be formed easily by using electro-plating or other surface processing technique. The rotor section may be of a shape such that the rate of the reluctance change is enhanced by the combination of the magnetic substance portion and the conductive substance portion.

Rotational position detection device

This detection device comprises a coil section and a rod section which is capable of linear displacement relative to the coil section. The rod section has a magnetic substance portion changing reluctance of a magnetic circuit passing through the coil section in accordance with the linear displacement and a conductive substance portion provided in part of the rod section where the reluctance is caused to increase relatively in such a manner that an eddy current path will be formed relative to flux. By this arrangement, in places where reluctance increases due to absence of the magnetic substance, reluctance is caused to further increase by the eddy current loss produced by presence of the conductive substance portion whereby the secondary side induced voltage level is further attenuated and the accuracy of detection can be improved. The rod section may be so constructed as to produce only the reluctance change due to the conductive substance portion. This detection device is applicable to detection of a piston rod position of a fluid powered cylinder.

Reluctance type linear position detection device

A coil section for being excited by a primary ac signal and producing a secondary output signal is provided on the open end side of a bag-cylinder main body. A material consisting of such substance and having such configuration that bring about reluctance change of a magnetic circuit passing through the coil section in accordance with displacement of a piston rod of the bag-cylinder is provided in a predetermined pattern about the piston rod. In a detection circuit, position detection data representing the position of the piston rod is obtained in response to the secondary output signal from the coil section. In a position establishing circuit, stop position data representing a desired position at which the piston rod should be stopped is established depending upon the diameter of a tire to be vulcanized. In a comparison and control circuit, stopping of the piston rod is controlled, in a specified step in a sequence for vulcanizing the tire, in accordance with comparison between the established stop position data and the position detection data. This control device can readily cope with tires of different diameters simply by changing the stop position data.

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Sayama, Japan

Yuji Matsuki